Calculate your cost
Start with the example below, then replace the wattage, daily runtime, and rate with the numbers for your microwave oven.
This setup uses about 9 kWh in a 30-day month.
Please enter valid values within the ranges shown.
| Schedule | Hours/day | Cost/month |
|---|---|---|
| Half runtime | 0.13 | $0.85 |
| Page example | 0.25 | $1.69 |
| Longer runtime | 0.38 | $2.54 |
Same 1,200-watt input and 18.83¢/kWh rate; only runtime changes.
Formula for the page example
1.2 kW × 0.25 hr × $0.1883 = $0.06 per day
Convert watts to kilowatts, multiply by the active hours used each day, then multiply by the electricity price in dollars per kWh. Multiply the daily result by 30 for the monthly estimate shown above.
How to read this estimate
A microwave draws a fair amount of power while it is on, but most cooking sessions last only a few minutes. That short runtime keeps the total cost low even when its wattage resembles a small heater's.
Use this as a baseline until you can check the label or measure the microwave oven directly. Model, settings, condition, climate, and household routine can all change the result.
What changes the cost?
- 01
Input wattage rather than advertised cooking output
- 02
Minutes used per day and selected power level
- 03
Food quantity and repeated reheating cycles
Ways to spend less
- Enter actual minutes of daily use rather than rounding up to hours.
- Cover food appropriately to shorten reheating time.
- Use the microwave for small portions instead of preheating a full oven.