Electric consumption calculator: watts to kWh to cost
Enter each appliance's watts, hours a day, and days a month; the calculator totals the kilowatt-hours and prices them at the U.S. average rate of 18.34 ¢/kWh or any state's rate. The math is kWh = watts × hours ÷ 1,000, and a “unit” on a bill is one kWh.
Rates are EIA residential averages through June 2026, refreshed Sep 9, 2026. Preset wattages are typical figures; use the nameplate on your own appliance when you have it.
Add your appliances
| Appliance | Watts | Hours/day | Days/month | Qty | kWh/month | Cost/month | Remove |
|---|---|---|---|---|---|---|---|
| 43.2 kWh | $7.92 | ||||||
| 22.5 kWh | $4.13 | ||||||
| 180 kWh | $33.01 | ||||||
| Total | 246 kWh | $45.06 | |||||
3 appliances use about 246 kWh a month (2,948 kWh a year), about $45.06 a month or $540.74 a year at the U.S. average rate. For a whole-home bill from a kWh figure, use the electricity cost calculator.
Common appliances at the U.S. average rate
| Appliance | Typical watts | Hours/day | kWh/month | Cost/month |
|---|---|---|---|---|
| Refrigerator | 60 W | 24 | 43.2 kWh | $7.92 |
| Central AC | 3,500 W | 8 | 840 kWh | $154.06 |
| Window AC | 900 W | 8 | 216 kWh | $39.61 |
| Space Heater | 1,500 W | 4 | 180 kWh | $33.01 |
| Electric Water Heater | 4,500 W | 2.5 | 338 kWh | $61.90 |
| Clothes Dryer | 3,000 W | 0.75 | 67.5 kWh | $12.38 |
| Washing Machine | 700 W | 0.5 | 10.5 kWh | $1.93 |
| Dishwasher | 1,500 W | 1 | 45.0 kWh | $8.25 |
| Television | 150 W | 5 | 22.5 kWh | $4.13 |
| Desktop Computer | 250 W | 6 | 45.0 kWh | $8.25 |
| Electric Vehicle Charger | 7,200 W | 2 | 432 kWh | $79.23 |
| Wi-Fi Router | 12 W | 24 | 8.6 kWh | $1.58 |
Each appliance page explains the wattage range, amps, and what the same usage costs in every state, for example how many watts a refrigerator uses.
How to calculate electricity consumption
- Find the watts. The nameplate or manual lists rated watts; for cycling loads such as refrigerators and air conditioners, use the averaged draw rather than the running wattage.
- Multiply by hours a day, then divide by 1,000 for kWh a day.
- Multiply by days a month for kWh a month, and by 12 for a year.
- Multiply by the rate. kWh × cents per kWh ÷ 100 gives dollars. A 1,500 W space heater running 4 hours a day is 180 kWh a month, about $33.01 at the U.S. average rate.
Related tools
- Electricity cost calculator: a whole-home bill from any kWh figure at any state's rate.
- Electricity bill estimator: a bill from home size and household profile.
- Appliance electricity usage: watts, amps, and kWh for every appliance in the inventory.
- Why is my electric bill so high?: what to check when the total surprises you.
Frequently asked questions
How do I convert watts to kWh?
Multiply the appliance's watts by the hours it runs, then divide by 1,000: kWh = watts × hours ÷ 1,000. A 1,500 W space heater running 4 hours uses 1,500 × 4 ÷ 1,000 = 6 kWh. Multiply by the days it runs for a monthly figure (180 kWh over 30 days).
How much does 1 kWh of electricity cost?
$0.18 at the U.S. average residential rate of 18.34 ¢/kWh (EIA, June 2026). State averages run from about 13¢ to over 50¢ per kWh, so pick your state in the calculator for a local figure. The all-in average already includes delivery and utility fees; locally billed taxes vary.
What is a unit of electricity?
On most bills a unit is one kilowatt-hour (kWh): 1,000 watts drawn for one hour, or 100 watts for ten hours. Watts measure how fast a device draws power; kilowatt-hours measure how much energy it used over time, which is what the utility charges for.
How many kWh does a refrigerator use per month?
About 43 kWh a month for a typical modern refrigerator averaging 60 W around the clock (the compressor cycles on and off, so the running wattage is higher), about $7.92 a month at the U.S. average rate. Older or larger units use more.
Source & Method
Preset wattages and runtimes are the same curated assumptions the appliance pages use; the kWh arithmetic is watts × hours × days ÷ 1,000. Costs price kWh at the EIA all-in average residential rate for the U.S. average or the chosen state (delivery and utility fees included; locally billed taxes vary). Nothing here is a bill forecast: it is the energy your listed appliances draw at the assumptions you enter.