Electricity cost calculator — estimate appliance running costs
Find out how much it costs to run a device from its wattage, daily hours of use, your billing days per month, and price per kilowatt-hour (kWh). Results show daily kWh, monthly kWh, monthly cost, and annual cost—ideal for TVs, PCs, heaters, and AC units. Compare long-term ownership with our fuel cost calculator or budget percentages via the percentage calculator.
How to calculate electricity usage
Utility bills charge for kilowatt-hours (kWh)—power (kW) multiplied by time (hours). Because device labels list watts, convert first:
daily kWh = (watts × hours per day) ÷ 1000
Monthly energy = daily kWh × days per month. Monthly cost = monthly kWh × your $/kWh rate. Annual cost ≈ monthly × 12 (ignoring seasonal rate changes).
Example costs at $0.12/kWh
| Device | Power | Use | Est. monthly |
|---|---|---|---|
| LED bulb | 10 W | 5 h/day | ~$0.02/mo @ $0.12 |
| Laptop | 65 W | 8 h/day | ~$1.87/mo |
| TV | 150 W | 5 h/day | ~$2.70/mo |
| Desktop PC | 300 W | 6 h/day | ~$6.48/mo |
| Space heater | 1500 W | 4 h/day | ~$21.60/mo |
| Window AC | 1200 W | 8 h/day | ~$34.56/mo |
Assumes 30 days/month at $0.12/kWh; your utility rate may differ.
What uses the most electricity at home?
Heating and cooling (furnaces, heat pumps, central AC) dominate many bills. Water heaters, clothes dryers, and old refrigerators follow. Portable space heaters and window AC units draw high watts—even a few hours daily add noticeable cost, as the table shows.
“Vampire” standby load from chargers and entertainment centers is smaller per device but adds up; smart strips and efficient ENERGY STAR models reduce baseline draw.
Finding your real kWh rate
Check your electric bill for price per kWh—sometimes split into supply and delivery. U.S. residential averages often land near $0.12–$0.18/kWh, but California, Hawaii, and New England rates can be higher; some utilities offer time-of-use plans with cheaper off-peak hours.
Limitations
Nameplate watts are maximum ratings; motors and compressors cycle on and off. Actual use may be lower than label. Taxes, fixed monthly fees, and tiered pricing are not modeled—this tool estimates variable energy portion from usage math.
Frequently Asked Questions include TV all-day cost and usage formulas.