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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).

更新日 検証済みの例：5

h
days
$
その他の設定
試す
Cost per month
$
Cost per month: $27.00
小数点以下の桁数：2；最も近い値へ、等距離なら末尾が偶数の値へ
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
計算方法 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.

Electricity cost calculatorについて

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.

計算例

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

照合元：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

照合元：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

照合元：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

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

よくある質問

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」の精度はどのくらいですか？

精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：5。 例えば、「1.5 kW heater, 4 h a day, 30 days at 0.15」はDOE method: 1500 W × 4 h ÷ 1000 = 6 kWh/day; × 30 × 0.15 = 27.00; × 12 = 324.00と照合しています。

この計算方法の出典は何ですか？

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.

この計算機について

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}}

出典

  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

出典と照合済み

この計算機には、独立した出典の解答を使った計算例が 5 件あります。テストに組み込まれており、ここでも実行できます。

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