Everyday calculators
Tips and bill splitting, discounts, unit prices, recipe scaling, grades and GPA, word counts, screen sizes, tyre sizes and shared-expense settling.
19 calculators, 107 checked worked examples.
Money
- Discount, markup and margin calculator
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.
- Group expense splitter for trips and parties
Expense splitter: enter who paid what to get each person's equal share and who owes whom, settled with the fewest possible payments.
- Tip calculator and bill splitter
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.
- Travel budget and jet lag calculator
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 comparison calculator
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.
- Wedding and event budget calculator
Split a wedding or event budget across categories by percentage or fixed amount, with the cost per guest and what is left to allocate.
Kitchen
- Recipe scaler
Scale a recipe to any number of servings: each ingredient is multiplied by new ÷ original servings, with cups and spoons shown as kitchen fractions.
- Oven temperature and pan size converter
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.
School
- GPA calculator
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
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.
Text
- Word counter and reading time calculator
Word counter: words, characters with and without spaces, sentences and paragraphs, plus reading time at 238 wpm and speaking time at 150 wpm.
- Case converter: title, sentence, upper and lower case
Convert text to title case, sentence case, UPPER or lower case, or to camelCase, snake_case and kebab-case, with character and word counts.
Tech
- PPI calculator for screen size and aspect ratio
PPI calculator: pixel density from resolution and diagonal, plus screen width and height, aspect ratio, dot pitch and the distance where pixels blend.
- Tire size and speedometer calculator
Tire diameter, sidewall height and revolutions per km from a size such as 225/45R17, and the speedometer error when you change tire sizes.
Fun
- Dog years and cat years calculator
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.
- Love calculator (just for fun)
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.
Vehicles
Sizes
Sports
How to choose a everyday calculator
Use a common basis for comparisons
Compare unit prices with the same quantity and unit, and decide whether tax belongs in the total. For a restaurant bill, set the tip basis and number of people explicitly. Shared expenses need each person's contribution and share rather than just a simple division of the total. Recipe scaling preserves ingredient ratios but does not guarantee that cooking time scales by the same factor. Review the assumptions shown beside each input.
Watch percentages, weights and rounding
A discount percentage and a markup percentage use different starting values. Course grades may be weighted by assessment category, while GPA is typically weighted by credits and a stated grading scale. Enter the weights your institution actually uses instead of treating every item equally. Currency totals may need whole-cent rounding, and physical portions may need practical rounding after calculation. Keep the unrounded result available when checking a multi-step calculation.