Electricity cost calculator

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

업데이트 2026년 9월 28일검증한 예제: 5

Cost per month

소수 자릿수: 2; 가장 가까운 값, 중간값은 끝자리가 짝수인 쪽으로

Cost per year: $324.00
Cost per day of use: $0.90
Cost per hour: $0.2250
Energy per day of use: 6kWh
Energy per month: 180kWh
Energy per year: 2,160kWh

The rated power is a maximum: fridges, ACs and heaters cycle on and off, so their real use is usually lower. Tariffs with slabs, fixed charges or time-of-day rates will differ.

Running it 4 h a day uses 6 kWh per day of use — 180 kWh a month, about $27.00 at $0.150 per kWh, or $324.00 a year.

Monthly cost with the same use (4 h a day, 30 days)

계산 방법 S

Power in kilowatts
$P = \frac{1{,}500\ \mathrm{W}\times 1}{1000} = 1.5\ \mathrm{kW}$
Energy per day
$E_{\text{day}} = 1.5\ \mathrm{kW}\times 4\ \mathrm{h} = 6\ \mathrm{kWh}$
Energy per month and year
$E_{\text{month}} = 6\times 30 = 180\ \mathrm{kWh},\quad E_{\text{year}} = 12\times E_{\text{month}} = 2{,}160\ \mathrm{kWh}$
Cost
$\text{cost}_{\text{month}} = 180\times 0.15 = 27,\quad \text{cost}_{\text{year}} = 324$
Money is shown rounded to the currency's minor unit; the year is 12 months of the pattern you entered.

Electricity cost calculator 소개

The calculator turns an appliance's power rating into energy and money. Energy per day is the power in kilowatts times the hours of use, in kilowatt-hours (kWh); the monthly figure multiplies that by the days used, the yearly one by 12 months, and each is priced at your tariff per kWh. A kWh is the "unit" counted on electricity bills.

People use it to compare appliances or to see what a heater or air conditioner adds to a bill. The default, a 1.5 kW heater running 4 hours a day for 30 days at 0.15 per kWh, uses 6 kWh a day and 180 kWh a month: 27.00 a month and 324.00 a year.

The rated wattage is a maximum. Fridges, air conditioners and heaters with thermostats cycle on and off, so their real use is lower, and tiered tariffs, standing charges and time-of-day rates change the final bill.

계산 예제

1.5 kW heater, 4 h a day, 30 days at 0.15

Appliance power: 1500 W
Hours used per day: 4 h
Days used per month: 30 days
Price per kWh (unit): 0.15

Energy per day of use: 6 kWh
Energy per month: 180 kWh
Cost per month: 27.00
Cost per year: 324.00

검증 출처: DOE method: 1500 W × 4 h ÷ 1000 = 6 kWh/day; × 30 × 0.15 = 27.00; × 12 = 324.00

100 W bulb, 5 h a day at 0.12

Appliance power: 100 W
Hours used per day: 5 h
Days used per month: 30 days
Price per kWh (unit): 0.12

Energy per month: 15 kWh
Cost per month: 1.80

검증 출처: Python 3.8 decimal: 0.1 kW × 5 × 30 × 0.12

Two 1 hp motors, 8 h on 22 working days at 0.20

Appliance power: 1 hp
Hours used per day: 8 h
Days used per month: 22 days
Price per kWh (unit): 0.20
Number of appliances: 2

Energy per day of use: 11.9312 kWh
Cost per month: 52.50
Cost per year: 629.97

검증 출처: Python 3.8 decimal: 2 × 745.69987 W × 8 h = 11.9312 kWh/day; × 22 × 0.20 = 52.4973

Ten 9 W LED bulbs, 6 h a day at ₹8

Appliance power: 9 W
Hours used per day: 6 h
Days used per month: 30 days
Price per kWh (unit): 8
Number of appliances: 10

Energy per month: 16.2 kWh
Cost per month: 129.60

검증 출처: Python 3.8 decimal: 10 × 9 W × 6 h × 30 = 16.2 kWh; × 8 = 129.60

자주 묻는 질문

How do I calculate the cost of running an appliance?

Multiply the power in kilowatts by the hours of use to get kilowatt-hours, then multiply by the price per kWh. A 2,000 W (2 kW) heater used for 3 hours uses 6 kWh; at 0.15 per kWh that costs 0.90. The US Department of Energy gives the same method: watts × hours used per day ÷ 1,000 = daily kWh.

What is a unit of electricity?

One unit is one kilowatt-hour (kWh): 1,000 watts used for one hour, which is 3.6 megajoules of energy. A 100 W bulb takes 10 hours to use one unit and a 2 kW kettle takes 30 minutes. Bills in the UK, India and many other countries count units, and the price per unit is the tariff to enter here.

How do I find an appliance's wattage?

Look for the rating label on the back or base of the appliance, or in its manual; it lists watts or kilowatts. If it gives only amps, multiply by the supply voltage, as the US Department of Energy suggests: 5 A at 230 V is 1,150 W. A plug-in energy meter measures real consumption, including standby power and thermostat cycling.

How much electricity does a fridge use?

Less than its rating suggests, because the compressor switches on and off. The US Department of Energy suggests dividing the hours a fridge is plugged in by three to estimate its full-power running time, so a 150 W fridge runs about 8 hours a day: 1.2 kWh a day, or 36 kWh in a 30-day month. The kWh-per-year figure on its energy label is a better guide when you have it.

“Electricity cost calculator”의 정확도는 어느 정도인가요?

정확도는 입력값과 계산 방법의 가정에 따라 달라집니다. 십진 연산은 유효숫자 50자리를 사용하지만, 추정값·수치해석 방법·원본 데이터의 정밀도는 더 낮을 수 있습니다. 표시값을 반올림해도 이러한 한계는 사라지지 않습니다. 독립적인 출처의 풀이와 대조한 계산 예시: 5. 예를 들어 “1.5 kW heater, 4 h a day, 30 days at 0.15”은 DOE method: 1500 W × 4 h ÷ 1000 = 6 kWh/day; × 30 × 0.15 = 27.00; × 12 = 324.00와 대조해 확인합니다.

이 계산 방법의 출처는 무엇인가요?

U.S. Department of Energy — Estimating appliance and home electronic energy use; BIPM SI Brochure (9th ed.), Table 8 — the kilowatt-hour is 3.6 MJ.

이 계산기 소개

E_{\text{day}} = \frac{P \times h \times n}{1000}\ \text{kWh},\quad \text{cost}_{\text{month}} = E_{\text{day}} \times d \times \text{tariff},\quad \text{cost}_{\text{year}} = 12 \times \text{cost}_{\text{month}}

출처

U.S. Department of Energy — Estimating appliance and home electronic energy use
BIPM SI Brochure (9th ed.), Table 8 — the kilowatt-hour is 3.6 MJ

출처와 대조하여 검증

이 계산기에는 독립적인 출처에서 답을 얻은 계산 예제가 5개 있습니다. 테스트 모음에서 실행되며 여기에서도 실행할 수 있습니다.

Monthly cost with the same use (4 h a day, 30 days)

Power in kilowatts

Energy per day

Energy per month and year

Cost