How much it costs to run an appliance, calculated from its power rating, how long it runs, and your electricity rate.
How it works
The appliance’s wattage is converted to kilowatts and multiplied by hours used to get energy consumed in kilowatt-hours, then multiplied by the price per kilowatt-hour to get cost.
What this does not include
This does not include tiered or time-of-use electricity rate structures — this calculator assumes a single flat rate per kilowatt-hour.
How to use this calculator
- Enter the appliance’s power rating, hours used, and your electricity price per kWh.
A worked example
A 1,500W appliance running 3 hours at $0.15/kWh: energy used = (1500×3)/1000 = 4.5 kWh, cost = 4.5 × 0.15 = $0.675.
A 100W device running 24 hours at $0.12/kWh: energy used = 2.4 kWh, cost = $0.288.
What the variables mean
| Variable | Meaning |
|---|---|
| Watts | Power draw of the device |
| Hours | Runtime |
| Price per kWh | Electricity rate from the utility bill |
Edge cases worth knowing
A high-wattage device running briefly can cost less than a low-wattage device running continuously — the second example’s 100W device left on all day approaches half the cost of the first example’s much more powerful 1,500W appliance run for just 3 hours.
Missing wattage makes the calculation impossible, so the calculator declines to show a result without it.
Frequently asked questions
Where do I find an appliance’s power rating?
Usually printed on a label on the appliance itself, or in its manual or product specifications, given in watts.
Where do I find my electricity price per kWh?
Your utility bill typically states this rate directly, sometimes broken down further by usage tier or time of day.
Why does this matter for budgeting?
High-wattage appliances used for long periods (like space heaters or dryers) can meaningfully affect an electricity bill, and this calculator helps quantify that cost directly.
