Electricity Cost Calculator
See what it costs to run an appliance by the day, month, and year from its wattage, your hours of use, and your electricity rate.
What your result means
This converts an appliance's wattage and run time into energy used (kWh) and multiplies by your rate to show daily, monthly, and yearly cost. It's the fast way to spot the energy hogs in your home. Also called an energy cost calculator. To total your whole home, use our electric bill calculator, or see the raw energy with the kWh calculator.
How to use this calculator
- Find the appliance wattage on its label or nameplate.
- Estimate how many hours a day it runs.
- Enter your electricity rate per kWh (check your bill).
- Read the daily, monthly, and yearly cost.
- Compare appliances to find what's driving your bill.
The formula
Watts times hours gives watt-hours; dividing by 1,000 gives kilowatt-hours, the unit your utility bills. Multiply by your rate for cost, then scale to a month or year.
Worked example
A 1,500 W space heater run 4 hours a day uses 6 kWh daily. At $0.17 per kWh that's about $1.02 a day, roughly $30.60 a month, or $372 over a year of that usage.
Monthly cost of common appliances ($0.17/kWh)
| Appliance | Watts × hours/day | ~Monthly cost |
|---|---|---|
| LED bulb | 10 W × 5 | $0.26 |
| Refrigerator | 150 W × 24 | $18.36 |
| Space heater | 1,500 W × 4 | $30.60 |
| Window AC | 1,000 W × 6 | $30.60 |
| EV charging | 7,200 W × 2 | $73.44 |
Tips & gotchas
- Always-on devices (fridge, well pump, aquarium) often cost more than occasional big loads.
- Heating and cooling dominate most bills — focus there for real savings.
- Check your actual rate; it varies widely by region and time of use.
- Phantom loads (chargers, standby electronics) add up — use smart strips.
- High running costs? Solar can offset them — see our solar calculators.
Frequently asked questions
How do I calculate the cost of running an appliance?
Multiply its wattage by hours used, divide by 1,000 for kWh, then multiply by your rate. A 1,500 W heater for 4 hours costs about $1.02 a day at $0.17/kWh.
What is the average cost of electricity?
The US residential average is around $0.17 per kWh, but it ranges widely by state and utility. Use the exact rate from your bill for accuracy.
What uses the most electricity at home?
Heating, cooling, water heating, and EV charging usually top the list, followed by always-on appliances like the refrigerator.
Is this an energy cost calculator too?
Yes — electricity cost and energy cost are the same calculation. Enter watts, hours, and your rate to get the running cost.
How can I lower my running costs?
Target the biggest, most-used loads first, cut phantom power, and consider solar to offset usage. The solar calculators can size and price a system.
Related calculators
Estimates only — see our full disclaimer.