Electricity cost calculator
Compare what an appliance costs to run under two usage patterns. Example values are editable and are not typical-use estimates.
Enter currency units, not cents or pence: 20 cents = 0.20. Currency selection changes the label only; it does not convert rates.
Your running costs
| Period | Current | Alternative |
|---|---|---|
| Daily kWh | 3.00 | 1.50 |
| Daily cost | $0.60 | $0.30 |
| 30-day cost | $18.00 | $9.00 |
| 365-day cost | $219.00 | $109.50 |
Alternative saves $109.50 per year under these assumptions.
Formula and worked example
Daily energy = watts ÷ 1,000 × hours. Cost = energy in kWh × price per kWh. A 1,500-watt appliance running for two hours uses 3 kWh. At 0.20 per kWh, that costs 0.60 per day, 18.00 per 30 days, or 219.00 per 365 days.
Where to find your inputs
Use measured average power from a suitable energy monitor or an appliance's energy label. A nameplate can describe maximum power rather than normal use. Fridges, heat pumps, and air conditioners cycle or vary their output: multiplying peak watts by every hour they are plugged in can overestimate consumption.
Does this predict my full electricity bill?
No. It estimates one load at a constant rate and constant daily usage. Fixed charges, taxes outside your entered rate, demand charges, seasonal changes, and time-of-use tariffs are excluded. For multiple tariffs, calculate each usage period separately. Use actual billing days when comparing against a bill.
What should I compare next?
Try reducing hours first, then compare a replacement appliance's measured power. Annual savings alone do not include the replacement price or differences in useful output. A lower-wattage heater may also provide less heat.
Read the electricity-cost guide or compare solar savings.
Reference: EIA's explanation of watts and kilowatt-hours.