This free electricity cost calculator shows how much any appliance costs to run, from a light bulb to a space heater, air conditioner or electric water heater. It turns watts into kWh and then into money, so you can see which devices drive up your electric bill. It works with any currency and any electricity rate.
How to use this calculator
- Pick an appliance from the list, or choose Custom and type its wattage.
- Enter how many you have and how many hours a day they run.
- Enter your electricity price per kWh from your bill.
The results update as you type. A month is taken as 30.4 days (365 ÷ 12).
How to calculate electricity cost
kWh per day = watts × quantity × hours per day ÷ 1000
Cost = kWh × price per kWh
First convert watts to kilowatt-hours (kWh), the unit on your bill, then multiply by your price per kWh. The same formula works for any appliance, from a phone charger to an electric oven.
Worked example: a 1500 W space heater
A 1500 W heater used 5 hours a day uses 1500 × 5 ÷ 1000 = 7.5 kWh per day. At $0.17 per kWh that is 7.5 × 0.17 = $1.28 per day, about $39 per month. If its thermostat keeps it on only half the time, the real cost is about half that.
How much does it cost to run common appliances?
Typical running costs at $0.17 per kWh, the approximate US average. Use the calculator above for your own rate and hours.
| Appliance | Watts | Hours / day | Cost / month | Cost / year |
|---|---|---|---|---|
| LED light bulb | 10 W | 5 | $0.259 | $3.10 |
| Wi-Fi router Always on |
10 W | 24 | $1.24 | $14.89 |
| Laptop | 60 W | 8 | $2.48 | $29.78 |
| Ceiling fan | 75 W | 8 | $3.10 | $37.23 |
| 55" LED TV | 100 W | 5 | $2.59 | $31.03 |
| Refrigerator Compressor runs about a third of the day |
150 W | 8 | $6.21 | $74.46 |
| Gaming PC While gaming |
400 W | 4 | $8.27 | $99.28 |
| Window air conditioner | 1,000 W | 8 | $41.37 | $496.40 |
| Space heater On full power |
1,500 W | 5 | $38.78 | $465.38 |
| Microwave 15 minutes a day |
1,100 W | 0.25 | $1.42 | $17.06 |
| Dishwasher One cycle a day |
1,800 W | 1 | $9.31 | $111.69 |
| Clothes dryer One load a day |
3,000 W | 1 | $15.51 | $186.15 |
| Central air conditioner Hot summer days |
3,500 W | 8 | $144.78 | $1,737.40 |
| Electric water heater Heating time, not hours of hot water |
4,000 W | 3 | $62.05 | $744.60 |
Electricity cost per hour by wattage
How much a device costs per hour of use at three common electricity prices.
| Power | At $0.10/kWh | At $0.17/kWh | At $0.30/kWh |
|---|---|---|---|
| 100 W | $0.01 | $0.017 | $0.03 |
| 500 W | $0.05 | $0.085 | $0.15 |
| 1,000 W | $0.10 | $0.17 | $0.30 |
| 1,500 W | $0.15 | $0.255 | $0.45 |
| 2,000 W | $0.20 | $0.34 | $0.60 |
| 3,000 W | $0.30 | $0.51 | $0.90 |
| 5,000 W | $0.50 | $0.85 | $1.50 |
Typical appliance wattage
| Appliance | Typical watts | Notes |
|---|---|---|
| LED bulb | 8–12 W | Replaces a 60 W incandescent |
| Laptop | 30–90 W | Less when idle |
| Refrigerator | 100–250 W | Compressor runs ~30–50% of the time |
| Gaming PC | 250–600 W | Under load; 60–100 W idle |
| Window AC | 500–1500 W | Cycles with thermostat |
| Space heater | 750–1500 W | Most US models max out at 1500 W |
| Clothes dryer | 2000–5000 W | Electric models |
How to lower your electric bill
- Find your biggest energy users first: the home energy usage calculator adds up every appliance in your home at once.
- Heating and cooling are usually the biggest loads — a thermostat change of 1 °C (2 °F) can save several percent.
- Replace old incandescent or halogen bulbs with LEDs; they use about 85% less energy.
- Use a smart plug or power strip to cut standby power from TVs, consoles and chargers.
- If your utility has time-of-use rates, run dishwashers, dryers and EV charging at off-peak times.
- Thinking about solar? Use the solar panel calculator to see how many panels would cover your usage. Driving electric? The EV charging cost calculator shows what charging adds to your bill.