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kWh Calculator

kWh = watts x hours / 1,000; a 1,000 W appliance running 5 hours uses 5 kWh, about $0.92 at the 18.31 cent U.S. average.

What do you want
W
Power in
h

EIA residential averages, July 2026.

¢/kWh

Edit it to match your bill.

Energy per day

5kWh

1,000 W for 5 h costs $0.92 at 18.31 cents per kWh.
Per month
152.1kWh, $27.85
Per year
1,825kWh, $334
Per hour running
1kWh
The math

  1. kWh per day

    1,000 W × 5 h ÷ 1,000 = 5 kWh

  2. Cost per day

    5 kWh × 18.31 ¢ ÷ 100 = $0.92

  3. Per month and year

    5 kWh × 365 ÷ 12, × 365 = 152.1 kWh, 1,825 kWh

State rates: EIA residential averages, July 2026.

A kilowatt-hour is 1,000 watts used for one hour, so kWh = watts × hours ÷ 1,000. A 1,000 W appliance running 5 hours uses 5 kWh, which costs about $0.92 at the 18.31 cent U.S. residential average. This kWh calculator has three modes: watts to kWh, the cost of a kWh amount, and your own price per kWh from a bill.

How kWh is calculated

Power (watts or kilowatts) is a rate; energy (kWh) is that rate held for time. Virginia Cooperative Extension, using the Department of Energy method, gives it as wattage × hours used per day ÷ 1,000 = daily kWh. Multiply by days for a longer period and by the rate for cost.

kWh = watts × hours ÷ 1,000; cost = kWh × price per kWh

For a load in kilowatts skip the ÷ 1,000: 3 kW for 2 hours is 6 kWh.

Worked example: 1,000 W for 5 hours a day

  • Energy per day: 1,000 W × 5 h ÷ 1,000 = 5 kWh
  • Cost per day: 5 kWh × $0.1831 = $0.92
  • Per month: 5 × 365 ÷ 12 = 152.1 kWh, $27.85
  • Per year: 1,825 kWh, $334.16

Watts to kWh quick reference

LoadTimeEnergy
100 W10 hours1 kWh
1,000 W1 hour1 kWh
1,500 W8 hours12 kWh
60 W24 hours1.44 kWh
5,000 W3 hours15 kWh

kWh cost: what a kWh amount costs

Choose kWh cost and enter the kWh used, for example a month's meter reading. 900 kWh at 18.31 cents is $164.79; each 100 kWh costs $18.31 and each 1,000 kWh $183.10. The state list is the average residential price from the Energy Information Administration for July 2026, from 12.72 cents in Louisiana to 48.00 cents in Hawaii.

kWh price: your price per kWh from a bill

Choose Price per kWh, enter the bill total and the kWh used on it. A $165 bill for 900 kWh is 165 ÷ 900 = 18.33 cents per kWh, close to the U.S. average. Bills include delivery, fixed fees and taxes, so this all-in price usually sits above the energy rate quoted by your supplier; use it when you want to know what one more kWh really costs you.

Reading the numbers

Use the watts on the nameplate or the label. A range means the appliance changes its draw, for example a refrigerator only draws its rated watts while the compressor runs. If a nameplate lists volts and amps instead, multiply them: 120 V × 12.5 A is 1,500 W.

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