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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).

Обновлено Проверенные примеры: 5

h
days
$
Другие параметры
Попробовать
Cost per month
$
Cost per month: $27.00
Знаков после запятой: 2; До ближайшего, при равенстве — к чётной цифре
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)

LED bulb 9 W$0.16Laptop 60 W$1.08Fridge 150 W$2.70Yours: 1.5 kW$27.00AC 1.8 kW$32.40
Как выполняется расчёт S

  1. Power in kilowatts

    P=1,500 W×11000=1.5 kWP = \frac{1{,}500\ \mathrm{W}\times 1}{1000} = 1.5\ \mathrm{kW}

  2. Energy per day

    Eday=1.5 kW×4 h=6 kWhE_{\text{day}} = 1.5\ \mathrm{kW}\times 4\ \mathrm{h} = 6\ \mathrm{kWh}

  3. Energy per month and year

    Emonth=6×30=180 kWh,Eyear=12×Emonth=2,160 kWhE_{\text{month}} = 6\times 30 = 180\ \mathrm{kWh},\quad E_{\text{year}} = 12\times E_{\text{month}} = 2{,}160\ \mathrm{kWh}

  4. Cost

    costmonth=180×0.15=27,costyear=324\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.

О калькуляторе: Electricity cost calculator

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.

Примеры с решением

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

Источник проверки: 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

Источник проверки: 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

Источник проверки: 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

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

Вопросы

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.

Насколько точен «Electricity cost calculator»?

Точность зависит от введённых данных и допущений метода. Десятичная арифметика использует 50 значащих цифр, но оценки, численные методы и исходные данные могут быть менее точными; округление на экране не устраняет эти ограничения. Решённые примеры, проверенные по независимым источникам: 5. Например, «1.5 kW heater, 4 h a day, 30 days at 0.15» проверяется по источнику DOE method: 1500 W × 4 h ÷ 1000 = 6 kWh/day; × 30 × 0.15 = 27.00; × 12 = 324.00.

Откуда взята методика?

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.

Об этом калькуляторе

Eday=P×h×n1000 kWh,costmonth=Eday×d×tariff,costyear=12×costmonthE_{\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}}

Источники

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

Проверено по источникам

В калькулятор включены решённые примеры с ответами из независимых источников. Их количество: 5. Они входят в набор тестов, и вы также можете запустить их здесь.

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