所有计算器

The nth term and the sum of the first n terms of an arithmetic or geometric sequence, the sum to infinity, and exact Fibonacci numbers, with a table.

Add, subtract, multiply and divide complex numbers, raise them to powers, find nth roots, and convert a + bi to polar form, with an Argand diagram.

The definite integral of any function f(x) between two limits, by adaptive Gauss–Kronrod quadrature to about 20 significant digits, with the area shaded.

Raise a number to any exponent, including fractional and negative ones, or take its square, cube or nth root, with exact simplified radicals such as 5√2.

Factor calculator: every factor and factor pair of a whole number up to 10¹⁸, its prime factorization, divisor count and sum, and perfect or abundant.

精确计算分数和带分数的加、减、乘、除，约分至最简形式，并将小数（包括循环小数）转换为分数。

Greatest common divisor (GCD, GCF or HCF) and least common multiple (LCM) of two or more whole numbers, with Euclid's algorithm step by step.

绘制多个函数、极坐标曲线和参数曲线；平移和缩放图形；求根、交点、极值点和面积。

The logarithm of a number to any base, including ln and log₁₀, with change-of-base steps, or the exponent x that solves bˣ = y, exact when rational.

Long division calculator that shows every step: quotient and remainder, the decimal quotient with its repeating block marked, and the fraction.

计算最大 6 × 6 矩阵的行列式、逆矩阵、秩和行最简形，展示每一步行运算；同时支持转置、乘积与求和，结果使用精确分数。

Average calculator for a list of numbers: mean, median, mode, range, count and sum, with the sorted data and the middle values highlighted.

Calculate a mod n under the floored, truncated and Euclidean conventions, modular powers a^b mod m of large numbers, and modular inverses, with steps.

The first or second derivative of any function f(x) at a point, to about 20 significant digits by Richardson extrapolation, with the tangent line drawn.

计算Y的X%、一个数占另一个数的百分比、百分比增减、百分比差异，以及增加百分比之前的原始值。

All real and complex roots of a polynomial up to degree 6, such as a cubic or quartic equation, with repeated roots found exactly and 30-digit accuracy.

Prime factorization of any whole number up to 60 digits, with a factor tree, a prime or composite verdict, its divisors and the nearest primes.

用求根公式求解 ax² + bx + c = 0：以根式或复数表示精确根，并提供判别式、顶点、对称轴和图像。

Simplify a ratio, solve a proportion a : b = c : x for the missing term, scale a ratio to a target, or split an amount in a given ratio, exactly.

Convert numbers to Roman numerals and Roman numerals to numbers, from 1 to 3,999 (3,999,999 with overlines), with the standard form of any numeral.

按指定小数位、有效数字或最接近的十或百的倍数进行舍入。提供九种规则，包括四舍六入五成双、向下取整和向上取整。

键盘式计算器，支持角度、弧度或百分度的三角函数，以及对数、幂、阶乘、记忆和历史记录；尽可能使用精确分数。

Scientific notation calculator: convert between decimal, scientific, E and engineering notation, and add, subtract, multiply or divide with sig-fig rules.

Union, intersection, differences and symmetric difference of two sets of numbers or words, with the Jaccard index and a Venn diagram.

Square root calculator: the root to up to 1,000 decimal places, simplest radical form (√72 = 6√2), a perfect-square check and cube or nth roots.

Solve 2 to 5 simultaneous linear equations exactly by Gauss–Jordan elimination, with every row operation shown, and detect no-solution or infinite cases.

Truth table of a Boolean expression in up to 6 variables, with the canonical sum of products, product of sums, minterms and maxterms.

Dot and cross products of two vectors in 2D or 3D, their magnitudes, the angle between them and the projection of one onto the other, with a drawing.

Weighted average calculator: enter values with weights, one pair per line, for the weighted mean, sum of weights and each value's contribution.

在十进制度、度分秒（DMS）、弧度、百分度、整周、角分、角秒和毫弧度之间换算。

计算矩形、三角形、梯形、圆、椭圆、正多边形和圆环等15种平面图形的面积与周长，并查看按比例绘制的图形。

由面积、周长、半径或直径中的任一值求其余值，并根据圆心角计算弧长、弦长、扇形面积和弓形面积。

根据三个点求圆心、半径、面积及圆的方程，同时显示标准式(x − h)² + (y − k)² = r²和一般式。

根据边数或一个角度，计算正多边形的内角和、各内角与外角，以及对角线数量。

根据顶点坐标，用鞋带公式计算简单多边形的面积、周长和形心，并逐项展示计算过程。

根据两个已知值，利用勾股定理和三角函数计算斜边、未知直角边、两个锐角、面积与周长。

根据垂直高差和水平距离计算角度、坡度百分比、屋顶坡度（每12单位升高x单位）、斜长及椽长系数。

计算两点间的距离、中点、斜率，给出直线的斜截式、一般式和点斜式，并求两条直线的交点。

根据三个测量值求三角形的边、角、面积、周长、高、内切圆半径和外接圆半径，并显示SSA情形的两个可能解。

以度、弧度或百分度计算sin、cos、tan、sec、csc和cot，给出15°整数倍处的精确值，以及反函数的全部解。

计算圆柱、圆锥、球、棱锥、棱柱、圆环体和椭球等14种立体的体积、表面积、斜高及以升表示的容量。

Calculate your 401(k) balance at retirement from salary, contribution rate and a two-tier employer match, with 2026 IRS limits and catch-up.

Amortization calculator: payment, dated schedule and yearly totals for monthly, biweekly or weekly payments, with principal and interest in each.

Calculate an annuity's future value from regular payments, the payout a lump sum buys over N years, or how long it lasts at a set withdrawal.

Calculate a loan's APR with fees by the Regulation Z actuarial method, the amount financed, the finance charge and the effective annual rate.

Auto loan calculator: monthly car payment with trade-in, amount owed, sales tax and fees, total interest, a payment schedule, or the price a budget buys.

Calculate European call and put prices and the Greeks (delta, gamma, theta, vega, rho) with the Black-Scholes-Merton model, including dividends.

Calculate a bond's price from its yield to maturity, or the YTM from its price, with current yield, Macaulay and modified duration and convexity.

Calculate the break-even point in units and sales revenue from fixed costs, price and variable cost, plus the volume needed for a target profit.

Canadian mortgage payment with semi-annual compounding, accelerated bi-weekly or weekly options, the CMHC insurance premium and the balance at renewal.

Calculate a monthly car lease payment from the price, residual value and money factor or APR, split into depreciation, finance charge and tax.

Calculate CD interest and maturity value from the APY or APR and compounding, convert APY to APR, and see what an early withdrawal penalty costs.

Calculate sales commission at a flat or tiered rate, total pay with base salary, the effective rate, and the sales needed to earn a target commission.

计算存款加定期投入的未来价值，支持任意复利频率，包括按日复利和连续复利。

Calculate how long a credit card balance takes to pay off on minimum payments versus a fixed monthly payment, and the interest each costs.

按最新每日参考汇率换算 160 种货币，显示汇率日期和 90 天历史图表。

Calculate enterprise value, equity value and value per share with a DCF: projected free cash flows plus a Gordon-growth terminal value.

Debt consolidation calculator: compare your debts with one loan — monthly payment, total interest, payoff time, APR with fees and the break-even rate.

Compare the debt snowball (smallest balance first) and avalanche (highest rate first): months to debt-free, total interest and payoff order.

Calculate your debt-to-income ratio (DTI), front-end and back-end, against lender limits, and the debt cut or income rise that reaches your target.

Calculate a depreciation schedule by straight-line, declining balance, double declining, sum-of-years' digits or units of production, with book value.

Down payment and closing costs you need, how long your savings take to reach them (or the monthly saving needed), and the PMI cost below 20% down.

FHA loan payment with the 1.75% upfront MIP, the annual MIP from HUD's current table, taxes and insurance, and a check against your county's 2026 loan limit.

Add GST, VAT or sales tax to a price, or remove it from a tax-inclusive price, with stacked state and local rates or India's CGST/SGST split.

Home equity you can borrow at your lender's CLTV limit, and HELOC payments in the interest-only draw period and the repayment period, or a fixed home equity loan.

Find how much house you can afford: the highest home price whose payment, tax, insurance, HOA and PMI fit the 28% and 36% debt-to-income limits.

Calculate income tax for India FY 2025-26 (new vs old regime), US federal 2025 and UK 2025-26, with take-home pay and marginal and effective rates.

Calculate what a purchase will cost after inflation, what your money will still buy, and your real return after inflation.

Find how much you can borrow from the monthly payment you can afford at your rate and term, and the price your down payment then buys.

计算住房、汽车或个人贷款的月供、总利息，以及包含提前还款的逐月还款计划。

估算包含房产税、保险、业主协会费用（HOA）和私人抵押贷款保险（PMI）的月供，并查看还款计划及额外还款节省的金额。

Mortgage payoff calculator: new payoff date, months and interest saved by extra monthly, yearly or one-time payments, or the extra to finish by a date.

Calculate NPV, IRR, modified IRR, payback and discounted payback for a series of periodic cash flows, with the NPV profile across rates.

Calculate US take-home pay per paycheck and per year: 2026 federal withholding (IRS Pub. 15-T), Social Security, Medicare, state tax and deductions.

Compare refinancing at your planned sale or payoff month. See payments, closing costs, remaining balances and savings with cash or financed fees.

Compare renting and buying a home: net worth from owning versus renting and investing the difference, year by year, and when buying pulls ahead.

Calculate a rental property's cap rate, NOI, monthly cash flow, cash-on-cash return and IRR, with a year-by-year projection of rent, value and equity.

Calculate how much you need to retire on inflation-adjusted expenses, the monthly saving that gets you there, and how the money runs down.

Calculate your required minimum distribution from the IRS Uniform Lifetime or joint table, your RMD starting age (73 or 75), and future RMDs.

Calculate ROI (total return) and CAGR (compound annual growth rate) from an investment's start and end values, over years or between two dates.

Calculate your 2026 Roth IRA contribution limit after the income phase-out, its growth, and whether a Roth or traditional IRA leaves more after tax.

Convert an annual salary to an hourly wage or hourly pay to salary, plus daily, weekly, biweekly, semimonthly and monthly pay.

Calculate how much to save each month to reach a savings goal by a date, or how long a monthly deposit takes to get there, with interest.

Calculate simple interest (I = P × r × t) and the maturity amount on a principal for a term in years, months or days.

估算每月共同基金定投（SIP）的到期价值，可选择每年增加投入，或计算达到目标所需的定投金额。

Calculate your average cost per share across several buys, unrealized profit and return, and the position size for your risk and stop loss.

Student loan calculator: payment, total interest and payoff date on the federal standard, tiered or extended plan or a custom term, with extra payments.

Solve for the future value, present value, interest rate or time of a lump sum from the other three, with any compounding, including continuous.

VA loan payment with the VA funding fee from the current table (first or later use, by down payment), the financed loan amount, taxes and insurance.

Calculate XIRR, the annualized return on cash flows made on irregular dates, and XNPV at your discount rate, matching Excel's actual/365 method.

Army body fat standard for 2026: your waist-to-height ratio, pass or fail against 0.55 (AD 2026-13), the largest passing waist for your height and margin.

Blood alcohol content (BAC) estimate by the Widmark formula from drinks, body weight and time, with the elimination curve and time back to zero.

Blood pressure category (AHA/ACC) for a systolic/diastolic reading, from normal to stage 2 and severe hypertension, with pulse pressure and MAP.

Glucose from mg/dL to mmol/L and back, and HbA1c to estimated average glucose (eAG) and IFCC mmol/mol, with ADA categories.

根据公制或英制身高和体重计算身体质量指数（BMI），并查看世界卫生组织的成人分类及对应身高的健康体重范围。

使用Mifflin-St Jeor、Harris-Benedict或Katch-McArdle公式估算基础代谢率（BMR），以及五种活动水平下的每日热量需求（TDEE）。

使用美国海军围度法、Jackson-Pollock 3点或7点皮褶法，或根据BMI估算体脂率，并显示脂肪量、去脂体重及ACE分类。

Body surface area (BSA) in m² from height and weight by the Mosteller, DuBois and Haycock formulas, with the spread between them.

How much caffeine is left in your body from up to three doses, based on its half-life, and when the level drops below an amount you choose.

设定减重、维持或增重的每日热量目标，并按天和每餐显示蛋白质、碳水化合物及脂肪的克数。

Calories burned by an activity from its MET value in the Compendium of Physical Activities, your body weight and the time spent.

Estimated conception date and fertile window from a due date, the last period or an ultrasound, with the likely range for each dating method.

Cycling power-to-weight (W/kg), speed and pace, or swimming pace per 100 m and 100 yd with your SWOLF score.

Dose by weight from a mg/kg rate and body weight, capped at the single and daily maximum, with the liquid volume in mL for a given strength.

eGFR from serum creatinine (mg/dL or µmol/L), age and sex by the race-free CKD-EPI 2021 equation, with optional cystatin C and the KDIGO G1–G5 stage.

Heart rate zones from your maximum heart rate (220 − age, Tanaka, Gulati for women, or measured) by the Karvonen or percent-of-max method, with a target heart rate.

根据身高和性别，使用Devine、Robinson、Miller和Hamwi公式计算理想体重，并查看健康BMI对应的体重范围。

Lean body mass (LBM) from height, weight and sex by the Boer, James and Hume formulas, with the implied body fat percentage.

One-rep max (1RM) from a set of reps with the Epley, Brzycki, Lombardi and O'Conner equations, plus training loads from 50 % to 100 %.

Ovulation date, fertile window and next period for the coming cycles, from the first day of your last period and your cycle length.

Next period date and the following 5 predicted periods, with each cycle's fertile window and ovulation day, from your last period and average cycle length.

Pregnancy due date from the last period, conception date or IVF transfer, with today's gestational age, trimester and milestones (ACOG).

Recommended pregnancy weight gain by pre-pregnancy BMI (IOM 2009), for singletons or twins, with the weekly rate and a week-by-week chart of your gain.

Daily protein intake in grams from body weight, goal and training level, using published g/kg ranges, with a per-meal split.

Running pace per km or mile from distance and time, or finish time or distance from pace, with even splits and Riegel race predictions.

Bedtimes for a wake-up time, or wake-up times for a bedtime, counted in 90-minute sleep cycles plus the time it takes to fall asleep.

Steps to distance in km and miles from a step length based on your height or measured, with walking time and calories from the ACSM equation.

VO2 max from the Cooper 12-minute run, the Rockport 1-mile walk or the resting heart-rate ratio, rated against Cooper Institute norms for age and sex.

Waist-to-hip ratio and waist-to-height ratio from tape measurements, with the WHO risk cut-offs, the NICE bands and the WHO waist size category.

Daily water intake in litres, glasses and fl oz from body weight, exercise and climate, compared with EFSA and US adequate intakes.

计算起始日期之前或之后指定天数、周数、月数、年数或工作日数的日期，并显示星期和移动的自然日数。

根据出生日期计算任意日期的准确年龄，以年、月、日表示，并显示下次生日及以月、周、天和小时计的年龄。

The deadline N business days after or before a start date, skipping weekends and the holidays you list, with the calendar days it spans.

Convert a Gregorian date to Hijri (Umm al-Qura and tabular), Hebrew, Persian, Indian national (Saka) and Julian dates, or a Julian date back.

实时显示距离任意时区指定日期与时间还剩或已过的天、小时、分、秒，并考虑时钟调整。

Day of the week for any date, past or future: the weekday in the Gregorian calendar, worked through step by step with Zeller's congruence.

计算两个日期之间的天数，也可按年、月、日、周和小时表示；还可排除周末及自定义假日，计算工作日。

Calculate work hours, breaks and weekly timesheets. Use dates and a time zone for overnight shifts across daylight-saving changes and repeated hours.

Leap year checker: whether a year has 366 days under the Gregorian rule, which test decides it, and the previous and next leap years.

Military time converter: 12-hour to 24-hour time and back, how it is spoken, time-zone letters with the Zulu equivalent, and a full-day chart.

Sunrise and sunset times for any place and date, with solar noon, day length and civil twilight, worked out with NOAA's solar calculator method.

Add and subtract hours, minutes and seconds from a list of durations, with the total as H:MM:SS, decimal hours, minutes and seconds.

将一个时区的时间转换为最多12个其他时区的当地时间，自动处理夏令时，并提供会议安排表格。

Unix timestamp converter: epoch seconds, milliseconds, microseconds or nanoseconds to an ISO 8601 UTC date and local time, and dates back to epoch time.

Week number for any date: ISO 8601 week and week-numbering year, US week number, day of the year, days left in the year and the quarter.

Convert g-force to m/s², m/s² to g, ft/s² and gal (cm/s²), using standard gravity g₀ = 9.80665 m/s² exactly.

英亩（ac）→ 公顷（ha）。使用精确换算系数换算，附换算表和计算步骤。

英亩（ac）→ 平方英尺（ft²）。使用精确换算系数换算，附换算表和计算步骤。

在度和弧度之间换算，也支持百分度、角分、角秒、周和毫弧度，π按50位数字参与计算。

换算平方英尺与平方米、英亩与公顷，以及平方英尺与印度土地单位（贡塔、森特、比格哈、马尔拉、卡纳尔、格朗德），并列明换算系数。

巴（bar）→ 磅每平方英寸（psi）。使用精确换算系数换算，附换算表和计算步骤。

厘米（cm）→ 英尺（ft）。使用精确换算系数换算，附换算表和计算步骤。

厘米（cm）→ 英寸（in）。使用精确换算系数换算，附换算表和计算步骤。

厘米（cm）→ 米（m）。使用精确换算系数换算，附换算表和计算步骤。

厘米（cm）→ 毫米（mm）。使用精确换算系数换算，附换算表和计算步骤。

Convert clothing sizes between US, UK, EU, German, Italian and Japanese labels for women's dresses and tops, men's suits and shirt collars.

根据根元素字号、父元素字号和 DPI，将 px 换算为 rem、em、pt、派卡、英寸和 mm。CSS 规定 1 in = 96 px = 72 pt。

依据King Arthur Baking和USDA的重量表，为面粉、糖、黄油等27种烘焙原料进行杯与克的双向换算。

将 GB 换算为 MB、TB 换算为 GB、GiB 换算为 GB，明确区分十进制前缀（kB、MB、GB、TB）和二进制前缀（KiB、MiB、GiB、TiB），并支持比特和字节。

将 Mbps 换算为 MB/s、Gbps 换算为 MB/s、kbps 换算为 kB/s。网络速度以比特每秒表示；文件大小和下载计量以字节表示。

摄氏度（°C）→ 华氏度（°F）。使用精确公式换算，附换算表和计算步骤。

摄氏度（°C）→ 开尔文（K）。使用精确公式换算，附换算表和计算步骤。

华氏度（°F）→ 摄氏度（°C）。使用精确公式换算，附换算表和计算步骤。

华氏度（°F）→ 开尔文（K）。使用精确公式换算，附换算表和计算步骤。

Convert g/cm³ to kg/m³, kg/m³ to lb/ft³ and lb/gal (ppg), and g/mL to kg/L, with exact factors from the 1959 pound and foot.

Calculate how long a file takes to download or upload from its size in MB, GB or TB and your internet speed in Mbps, allowing for protocol overhead.

根据焦耳、卡路里、英热单位和电子伏特的精确定义，将 kWh 换算为 BTU、卡路里换算为焦耳、kcal 换算为 kJ，以及撒姆换算为 kWh。

英尺（ft）→ 厘米（cm）。使用精确换算系数换算，附换算表和计算步骤。

英尺（ft）→ 英寸（in）。使用精确换算系数换算，附换算表和计算步骤。

英尺（ft）→ 米（m）。使用精确换算系数换算，附换算表和计算步骤。

英尺（ft）→ 英里（mi）。使用精确换算系数换算，附换算表和计算步骤。

使用美制加仑与立方英尺的精确值，为水泵、管道和通风换算L/min到gpm、gpm到L/min、cfm到m³/h及m³/h到L/s。

Convert kgf to newtons, lbf to N and kN to kgf or lbf, using standard gravity (9.80665 m/s²) and the exact pound-force of 4.4482216152605 N.

Convert rpm to Hz, Hz to rpm, BPM to Hz, GHz to MHz and hertz to radians per second (ω = 2πf), from Hz to THz.

在 mpg、L/100 km 和 km/L 之间换算，支持美制和英制加仑：L/100 km = 235.215 ÷ US mpg 或 282.481 ÷ UK mpg。

吉字节（GB）→ 兆字节（MB）。使用精确换算系数换算，附换算表和计算步骤。

吉字节（GB）→ 太字节（TB）。使用精确换算系数换算，附换算表和计算步骤。

克（g）→ 千克（kg）。使用精确换算系数换算，附换算表和计算步骤。

克（g）→ 盎司（oz）。使用精确换算系数换算，附换算表和计算步骤。

克（g）→ 磅（lb）。使用精确换算系数换算，附换算表和计算步骤。

公顷（ha）→ 英亩（ac）。使用精确换算系数换算，附换算表和计算步骤。

使用精确的 1 英寸等于 2.54 cm 的定义，在厘米与英尺英寸之间换算身高，并将千克换算为磅或英石加磅。

机械马力（hp）→ 千瓦（kW）。使用精确换算系数换算，附换算表和计算步骤。

英寸（in）→ 厘米（cm）。使用精确换算系数换算，附换算表和计算步骤。

英寸（in）→ 英尺（ft）。使用精确换算系数换算，附换算表和计算步骤。

英寸（in）→ 毫米（mm）。使用精确换算系数换算，附换算表和计算步骤。

开尔文（K）→ 摄氏度（°C）。使用精确公式换算，附换算表和计算步骤。

开尔文（K）→ 华氏度（°F）。使用精确公式换算，附换算表和计算步骤。

千卡（kcal）→ 千焦（kJ）。使用精确换算系数换算，附换算表和计算步骤。

千克（kg）→ 克（g）。使用精确换算系数换算，附换算表和计算步骤。

千克（kg）→ 磅（lb）。使用精确换算系数换算，附换算表和计算步骤。

千克（kg）→ 英石（st）。使用精确换算系数换算，附换算表和计算步骤。

千焦（kJ）→ 千卡（kcal）。使用精确换算系数换算，附换算表和计算步骤。

千米每小时（km/h）→ 米每秒（m/s）。使用精确换算系数换算，附换算表和计算步骤。

千米每小时（km/h）→ 英里每小时（mph）。使用精确换算系数换算，附换算表和计算步骤。

千米（km）→ 英里（mi）。使用精确换算系数换算，附换算表和计算步骤。

千帕（kPa）→ 磅每平方英寸（psi）。使用精确换算系数换算，附换算表和计算步骤。

千瓦（kW）→ 机械马力（hp）。使用精确换算系数换算，附换算表和计算步骤。

节（kn）→ 英里每小时（mph）。使用精确换算系数换算，附换算表和计算步骤。

Convert lakh and crore to million and billion, and write any number in words in the Indian and international systems, or turn words back into digits.

使用精确系数换算英里与千米、英尺与米、英寸与厘米，以及其他16种长度单位。支持同时输入英尺和英寸，例如 5 ft 11 in。

升每100千米（L/100 km）→ 英里每美制加仑（mpg (US)）。使用精确公式换算，附换算表和计算步骤。

升（L）→ 毫升（mL）。使用精确换算系数换算，附换算表和计算步骤。

升（L）→ 美制杯（cup）。使用精确换算系数换算，附换算表和计算步骤。

升（L）→ 美制加仑（gal）。使用精确换算系数换算，附换算表和计算步骤。

兆比特每秒（Mbit/s）→ 兆字节每秒（MB/s）。使用精确换算系数换算，附换算表和计算步骤。

兆字节（MB）→ 吉字节（GB）。使用精确换算系数换算，附换算表和计算步骤。

米每秒（m/s）→ 千米每小时（km/h）。使用精确换算系数换算，附换算表和计算步骤。

米（m）→ 厘米（cm）。使用精确换算系数换算，附换算表和计算步骤。

米（m）→ 英尺（ft）。使用精确换算系数换算，附换算表和计算步骤。

米（m）→ 英寸（in）。使用精确换算系数换算，附换算表和计算步骤。

米（m）→ 码（yd）。使用精确换算系数换算，附换算表和计算步骤。

公吨（t）→ 磅（lb）。使用精确换算系数换算，附换算表和计算步骤。

英里每小时（mph）→ 千米每小时（km/h）。使用精确换算系数换算，附换算表和计算步骤。

英里（mi）→ 英尺（ft）。使用精确换算系数换算，附换算表和计算步骤。

英里（mi）→ 千米（km）。使用精确换算系数换算，附换算表和计算步骤。

毫升（mL）→ 升（L）。使用精确换算系数换算，附换算表和计算步骤。

毫升（mL）→ 美制杯（cup）。使用精确换算系数换算，附换算表和计算步骤。

毫升（mL）→ 美制液量盎司（fl oz）。使用精确换算系数换算，附换算表和计算步骤。

毫米（mm）→ 厘米（cm）。使用精确换算系数换算，附换算表和计算步骤。

毫米（mm）→ 英寸（in）。使用精确换算系数换算，附换算表和计算步骤。

牛顿米（N·m）→ 磅英尺（lbf·ft）。使用精确换算系数换算，附换算表和计算步骤。

盎司（oz）→ 克（g）。使用精确换算系数换算，附换算表和计算步骤。

盎司（oz）→ 磅（lb）。使用精确换算系数换算，附换算表和计算步骤。

磅英尺（lbf·ft）→ 牛顿米（N·m）。使用精确换算系数换算，附换算表和计算步骤。

磅（lb）→ 千克（kg）。使用精确换算系数换算，附换算表和计算步骤。

磅（lb）→ 盎司（oz）。使用精确换算系数换算，附换算表和计算步骤。

磅（lb）→ 英石（st）。使用精确换算系数换算，附换算表和计算步骤。

换算 hp 与 kW、瓦特与马力，以及 BTU/h 与冷吨，区分机械马力（745.7 W）和公制马力（735.5 W）。

换算 psi 与 bar，以及 kPa、atm、hPa、mmHg 和 inHg，适用于轮胎、气象和血压读数，并展示精确的换算因子链。

磅每平方英寸（psi）→ 巴（bar）。使用精确换算系数换算，附换算表和计算步骤。

磅每平方英寸（psi）→ 千帕（kPa）。使用精确换算系数换算，附换算表和计算步骤。

Convert shoe sizes between US men's and women's, UK, EU, India, Japan and Mondopoint via foot length, using the ISO/TS 19407 formulas.

Convert between SI metric prefixes such as giga, mega, kilo, milli, micro and nano, from quecto (10⁻³⁰) to quetta (10³⁰), including the 2022 additions.

使用精确系数将 mph 换算为 km/h、km/h 换算为 mph，以及 m/s 和节；还支持 ft/s、海平面马赫数和光速。

平方英尺（ft²）→ 英亩（ac）。使用精确换算系数换算，附换算表和计算步骤。

平方英尺（ft²）→ 平方米（m²）。使用精确换算系数换算，附换算表和计算步骤。

平方米（m²）→ 平方英尺（ft²）。使用精确换算系数换算，附换算表和计算步骤。

英石（st）→ 千克（kg）。使用精确换算系数换算，附换算表和计算步骤。

英石（st）→ 磅（lb）。使用精确换算系数换算，附换算表和计算步骤。

用 °F = °C × 9/5 + 32 换算摄氏度与华氏度，并将两者换算为开尔文。支持兰氏度和列氏度；拒绝低于绝对零度的值。

太字节（TB）→ 吉字节（GB）。使用精确换算系数换算，附换算表和计算步骤。

将分钟换算为小时、小时换算为天、周换算为天、年换算为秒，范围从纳秒到千年，采用 365.2425 天的格里高利历年。

为扭矩扳手和螺栓规格换算 N·m 与 lb-ft，以及 lb-in 和 kgf·m，使用精确关系 1 lbf·ft = 1.3558179483314004 N·m。

美制杯（cup）→ 毫升（mL）。使用精确换算系数换算，附换算表和计算步骤。

美制杯（cup）→ 美制液量盎司（fl oz）。使用精确换算系数换算，附换算表和计算步骤。

美制杯（cup）→ 美制汤匙（tbsp）。使用精确换算系数换算，附换算表和计算步骤。

美制液量盎司（fl oz）→ 毫升（mL）。使用精确换算系数换算，附换算表和计算步骤。

美制液量盎司（fl oz）→ 美制杯（cup）。使用精确换算系数换算，附换算表和计算步骤。

美制加仑（gal）→ 升（L）。使用精确换算系数换算，附换算表和计算步骤。

英里每美制加仑（mpg (US)）→ 升每100千米（L/100 km）。使用精确公式换算，附换算表和计算步骤。

美制品脱（pt）→ 美制杯（cup）。使用精确换算系数换算，附换算表和计算步骤。

美制夸脱（qt）→ 升（L）。使用精确换算系数换算，附换算表和计算步骤。

美制短吨（ton (US)）→ 磅（lb）。使用精确换算系数换算，附换算表和计算步骤。

美制汤匙（tbsp）→ 毫升（mL）。使用精确换算系数换算，附换算表和计算步骤。

美制汤匙（tbsp）→ 美制杯（cup）。使用精确换算系数换算，附换算表和计算步骤。

美制汤匙（tbsp）→ 美制茶匙（tsp）。使用精确换算系数换算，附换算表和计算步骤。

美制茶匙（tsp）→ 毫升（mL）。使用精确换算系数换算，附换算表和计算步骤。

美制茶匙（tsp）→ 美制汤匙（tbsp）。使用精确换算系数换算，附换算表和计算步骤。

精确换算加仑到升、杯到mL、液体盎司到mL，并区分美制与英制的加仑、品脱和液体盎司。

按1959年磅的精确定义换算kg与磅、英石到kg、盎司到克，也支持吨、克拉、金衡盎司和托拉。

码（yd）→ 米（m）。使用精确换算系数换算，附换算表和计算步骤。

Light travel time for any distance, apparent and absolute magnitude from the distance modulus, and redshift to recession velocity (relativistic Doppler).

Centripetal force and acceleration from mass, speed and radius; rpm to rad/s and period; moment of inertia of nine shapes; torque from force and lever arm.

Solve C₁V₁ = C₂V₂ for any dilution variable, get molarity, % w/v and ppm from a weighed mass, the mass to weigh for a solution, or molality.

Electricity cost of running an appliance per hour, day, month and year, from its wattage, hours of use and your price per kWh (unit).

Solve Newton's second law F = ma for force, mass or acceleration, or find acceleration, normal force and friction for a block on an inclined plane.

Convert grams to moles and particles for any chemical formula, and find the limiting reagent, theoretical yield and leftover excess of a balanced reaction.

Half-life calculator: amount left, starting amount, elapsed time or half-life from N = N₀·2^(−t/t½), with carbon-14 and other isotope presets.

Horsepower from torque and rpm (hp = lb-ft × rpm ÷ 5252) or from quarter-mile ET and trap speed, with crank vs wheel horsepower and drivetrain loss.

Solve the ideal gas law PV = nRT for pressure, volume, moles or temperature in any units, or find a new state with the combined gas law.

Kinematics calculator for the SUVAT equations: enter three of displacement, initial and final velocity, acceleration and time to get the other two.

Kinetic energy (½mv²), potential energy (mgh), spring energy, work (Fd cos θ) and power (W/t), solved for any variable, plus the speed after a drop.

Molar mass in g/mol and mass percent composition of any chemical formula, with brackets and hydrates such as CuSO4·5H2O, from IUPAC 2021 atomic weights.

Momentum and collision calculator: final velocities, total momentum and kinetic energy lost in an elastic, inelastic or partly elastic head-on collision.

Ohm's law calculator: enter any two of voltage, current, resistance and power to get the other two, shown in the units you pick (mA, kΩ…).

Orbital velocity and period, escape velocity, surface gravity, your weight on the Moon or Mars, and the gravitational force between two masses.

Percent error from measured and accepted values, and uncertainty propagation through sums, products, quotients and powers, in quadrature or worst case.

Calculate pH, pOH, [H⁺] and [OH⁻] from a concentration, a strong acid or base, a weak acid's Ka or pKa, or a Henderson–Hasselbalch buffer.

Projectile motion calculator: range, maximum height, time of flight and impact speed for any launch angle and height, on Earth or other worlds, with drag.

RC and RL time constant and the time to charge or discharge to any percent; series RLC resonant frequency, impedance, phase, Q factor and bandwidth.

Resistor colour code calculator for 4, 5 and 6-band resistors: colours to ohms and tolerance, or a value to its bands, snapped to E12, E24 or E96.

Series and parallel resistor calculator: total resistance of any number of resistors, plus capacitors or inductors in series or parallel.

Heat energy from Q = mcΔT (solve for heat, mass, final temperature or specific heat), latent heat Q = mL for melting or boiling, and Carnot efficiency.

Thin lens and mirror equation for image distance, object distance or focal length, with magnification; Snell's law refraction and critical angle.

Voltage divider output, or R1 or R2 for a target voltage; the current-limiting resistor for LEDs with its nearest E12 value and power rating.

Voltage drop over a DC, single-phase or three-phase cable run, plus AWG wire size to diameter, mm², kcmil and resistance per km, and back.

Convert wavelength to frequency and photon energy, or back, with c = fλ and E = hf, and see where the wave sits in the electromagnetic spectrum.

Binomial distribution calculator: exact P(X = k), P(X ≤ k), tails and ranges for binomial, Poisson, geometric, negative binomial and hypergeometric.

Chi-square test calculator for goodness of fit and independence in a contingency table: χ², p-value, expected counts and Cramér's V.

Confidence interval calculator for a mean (t or z), a proportion (Wilson or Wald) or a difference of two means, with the margin of error and both bounds.

Correlation coefficient calculator: Pearson's r or Spearman's rank correlation for paired data, with r², a t statistic and a two-sided p-value.

Descriptive statistics calculator: mean, median, mode, standard deviation, variance, quartiles, IQR, outliers, skewness and kurtosis, with a histogram.

Exact probability of dice sums, coin-flip heads and streaks, drawing special cards from a deck and each 5-card poker hand, as a fraction and 1 in N.

Calculate expected value E[X], variance and standard deviation for a bet, game or decision from its outcomes and their probabilities or weights.

Grade curve calculator: rescale a class's scores to a target mean and standard deviation, or add flat points, with z-scores and percentile ranks.

Linear regression calculator: least-squares line of best fit with R², standard errors, p-values and predictions, plus polynomial and exponential fits.

Normal distribution calculator: z-scores, the probability below, above or between values, and the value at any percentile (inverse normal).

Convert odds between fractional, decimal and American (moneyline) formats and get the implied probability, worked in exact fractions.

One-way ANOVA calculator: the F statistic, p-value, sums of squares, mean squares and η² for two or more groups, with the full ANOVA table.

Calculate nCr and nPr exactly: combinations and permutations with or without repetition, for poker hands, lottery odds and PIN codes.

Calculate P(A or B), P(A and B) and P(A | B) for two events, or apply Bayes' theorem to a test result, with a probability tree and Venn diagram.

Generate random numbers from a seed: integers in a range, decimals, lottery-style draws without repeats and dice rolls, repeatable with xoshiro256**.

Sample size calculator for surveys and studies: n for a margin of error on a proportion or mean, and the per-group n for a target power.

t-test calculator for one-sample, two-sample (Welch or pooled) and paired tests, plus z-tests for a mean or proportion: p-value, critical value, decision.

t, chi-square and F distribution calculator: tail areas, p-values, densities and critical values, plus exponential and uniform distributions.

Air conditioner size for a room in BTU/h, tons and kW from floor area, ceiling height, insulation, sun and occupants, beside the Energy Star chart.

Board foot calculator: board feet, linear feet, volume and cost for a stack of lumber, at nominal size and at the dressed size of a 2x4, 2x6 and more.

Brick calculator: bricks or blocks for a wall from its size, openings, unit size and joint, with count per m² or ft², mortar volume and waste.

Total cost of owning a car over 1–15 years: depreciation, fuel, insurance, maintenance and loan interest, per year, per km and per mile.

Calculate concrete volume and bags for slabs, footings, columns or steps. Compare bag and ready-mix quotes with delivery fees, minimums and order increments.

Deck boards, joists and screws or hidden clips for a rectangular deck, from its size, joist spacing, board width, gap and waste allowance.

Drywall sheets for a room's walls and ceiling after doors and windows, with screws, joint tape and compound, for 4 × 8 ft or metric plasterboard.

Breaker size for one circuit: total watts and amps from a list of appliances, with the NEC 125% continuous-load rule and NEC or IEC breaker ratings.

EV charging cost and time between two battery levels at any charger power, with range added and cost per 100 km or miles against petrol.

Fence calculator: posts, rails, pickets and bags of concrete for a straight fence run, from its length, post spacing, picket width and gap.

Tile calculator: tiles and boxes for a floor or wall from room size, tile size, grout joint and waste allowance, plus grout in litres and kg.

Gravel calculator: cubic metres, cubic yards, tonnes, bags and truck loads of gravel, sand, topsoil or mulch for an area and depth.

Paint calculator: litres, US gallons and whole cans of paint and primer for a room, from wall area minus doors and windows, coats and coverage.

Pool volume in gallons, litres and m³ for rectangular, round or oval pools and water tanks, with fill time and the chlorine dose to raise ppm.

Roof area, squares and shingle bundles from building size and pitch, with underlayment rolls, ridge cap and the IRC minimum slope check.

Floor area in square metres and square feet, wall area, perimeter and volume for one or more rectangular rooms or an L-shaped room.

How many solar panels you need: system size in kW, panel count, yearly kWh, installed cost and payback from your use and peak sun hours.

Number of steps, riser height, tread depth, stringer length and stair angle from total rise and run, checked against IRC riser and tread limits.

Fuel cost of a trip from distance, mpg or L/100 km and fuel price, with tolls, a round-trip option and the cost split per person.

Wallpaper calculator: rolls to buy from wall width and height, roll size, pattern repeat and trimming, counted as full-height drops per roll.

Bra size calculator: band and cup from underbust and bust in inches or cm, in US, UK, EU, FR/BE and AU sizes, with sister sizes and the method stated.

Convert text to title case, sentence case, UPPER or lower case, or to camelCase, snake_case and kebab-case, with character and word counts.

Sale price after one or more percent-off discounts, and selling price from cost using a markup or a profit margin, with each converted to the other.

Dog years and cat years calculator: a pet's age in human years from the AAHA/Zoetis size chart or the International Cat Care table, for fun comparisons.

Gas mileage calculator: MPG (US and UK), L/100 km and km/L from odometer readings and fuel added, cost per mile, and a fill-up log with trend chart.

Golf handicap calculator: World Handicap System Handicap Index from your score differentials (best 8 of 20), then course and playing handicap for any tee.

GPA calculator: credit-weighted grade point average on the 4.0 scale from letter grades, plus percentage-to-GPA and CBSE CGPA-to-percentage conversions.

Grade calculator for weighted categories: your current course grade, and the score you need on the final exam or remaining work to reach a target.

Expense splitter: enter who paid what to get each person's equal share and who owes whom, settled with the fewest possible payments.

For entertainment only: a love compatibility score from 0 to 100 made from two names. The same pair always gets the same score; it predicts nothing.

Convert oven temperatures between °C, °F, fan oven and gas mark, and work out how much to scale a recipe for a different round, square or rectangular pan.

PPI calculator: pixel density from resolution and diagonal, plus screen width and height, aspect ratio, dot pitch and the distance where pixels blend.

Scale a recipe to any number of servings: each ingredient is multiplied by new ÷ original servings, with cups and spoons shown as kitchen fractions.

Tip calculator for any bill: tip on the pre-tax or after-tax total, then split it evenly or by shares, with each person's share rounded up.

Tire diameter, sidewall height and revolutions per km from a size such as 225/45R17, and the speedometer error when you change tire sizes.

Trip budget from daily spending per person, fixed costs and a contingency, plus how many days of jet lag to expect after crossing time zones.

Unit price calculator: compare up to four pack sizes by price per kg, litre, 100 g, ounce or item to see which is cheapest and by how much.

Split a wedding or event budget across categories by percentage or fixed amount, with the cost per guest and what is left to allocate.

Word counter: words, characters with and without spaces, sentences and paragraphs, plus reading time at 238 wpm and speaking time at 150 wpm.

Find the aspect ratio of any resolution, such as 1920 × 1080 = 16:9, resize it to a new width or height, or fit it in a screen with letterbox bars.

Download or upload time for a file at a given speed, the data a link moves in a set time, and a website's monthly bandwidth from page views.

Encode or decode Base64, URL-safe Base64, URL percent-encoding, HTML entities, hex bytes and Unicode code points, with UTF-8 and UTF-16 byte counts.

Operation counts and running times for O(1), O(log n), O(n), O(n log n), O(n²), O(n³), O(2ⁿ) and O(n!) at your input size, on a log-scale chart.

Convert numbers between binary, decimal, hex, octal and any base 2–36, including fractions, repeating digits and two's-complement bits for negatives.

Bitwise AND, OR, XOR, NOT, NAND, NOR, shifts and rotates on 8- to 64-bit integers, shown in decimal, hex and binary with a bit-by-bit grid.

How a color looks with protanopia, deuteranopia or tritanopia (red, green or blue color blindness), using the Machado et al. (2009) model.

Convert a color from HEX to RGB, HSL, HSV, CMYK, CIE Lab and OKLCH or back, and find its nearest CSS named color and relative luminance.

Check the WCAG 2.2 contrast ratio between a text color and its background, with AA and AAA pass or fail for normal text, large text and UI parts.

Generate complementary, analogous, triadic, split-complementary, tetradic or monochromatic color palettes from one base color, with HEX codes.

Translate a five-field cron expression or crontab line into plain English and list its next run times after any start date and time, in UTC.

Generate MD5, SHA-1, SHA-256, SHA-512 and CRC-32 hashes of any text, check them against a published checksum, and see the avalanche effect.

Format (pretty-print) or minify JSON and validate it against RFC 8259, with the line and column of any syntax error explained in plain words.

Check a password's entropy in bits and its average brute-force crack time at a chosen guess rate, or generate a password from a reproducible seed.

Calculate usable RAID capacity, parity or mirror overhead and how many drive failures RAID 0, 1, 5, 6 and 10 survive, in TB and the TiB Windows shows.

Find the network address, broadcast, usable host range and host count of any IPv4 or IPv6 CIDR block, with netmask, wildcard and equal subnets.

Generate reproducible UUID v4 and v7 values from a seed, or validate any UUID or GUID and decode its version, variant and embedded timestamp.

Air pressure at altitude from the standard atmosphere, with temperature, air density and the boiling point of water, or the altitude for a given pressure.

Life path number calculator: a birth date reduced to a numerology number from 1 to 9, or the master numbers 11, 22 and 33, with every step shown.

Moon phase for any date and time: the phase name, percentage illuminated and moon age in days, with the dates of the next new and full moons.

Carbon footprint calculator: yearly tonnes of CO₂e from driving, flights, train and bus, home electricity and diet, using UK government emission factors.

Rainwater harvesting calculator: yearly litres or gallons a roof collects from its area, rainfall and efficiency, and the share of household use it covers.

Wind chill and heat index calculator: the feels-like temperature from the NWS formulas, plus dew point, frostbite risk and heat-stress level.

Zodiac sign calculator: your star sign and its element from a birth date, plus the Chinese zodiac animal, element and yin or yang. For entertainment.