Battery & energy
Appliance Running Cost Calculator
Appliance energy equals watts multiplied by operating hours and divided by 1,000. Running cost equals that kilowatt-hour total multiplied by your electricity rate.
Estimate appliance energy use and operating cost from wattage, daily runtime, days, and your electricity rate.
Calculated result
Appliance operating cost
Calculating…
Calculated locally in your browser
Planning math only. Verify equipment specifications and installation requirements separately.
What this calculator returns
Use measured average watts for cycling or variable-power equipment when available.
Formula and variables
The calculation runs entirely in your browser. Static formulas, definitions, examples, and tables remain readable without JavaScript.
Daily kWh = watts x hours per day / 1000; cost = kWh x days x price per kWh.
- W
- Average real power in watts.
- h
- Operating or charging time in hours.
- kWh
- Accumulated electrical energy in kilowatt-hours.
- rate
- User-entered electricity price per kilowatt-hour.
- η
- User-entered efficiency expressed as a decimal or percentage.
Watts is input power, hours is average daily runtime, days is the period, and rate is your entered price per kWh.
Worked example
| Input | Value |
|---|---|
| Appliance power | 1500 W |
| Hours per day | 2 h/day |
| Number of days | 30 days |
| Electricity rate | 0.15 $/kWh |
A 1,500 W appliance used 2 hours per day for 30 days consumes 90 kWh and costs $13.50 at $0.15/kWh.
Reference table
| Appliance | Planning watts | Use note |
|---|---|---|
| LED lamp | 10 W | Nominal example |
| Laptop computer | 60–120 W | Typical planning range |
| Refrigerator while running | 100–250 W | Cycling load; startup can be higher |
| Microwave oven | 900–1,500 W | Input varies by model |
| Portable space heater | 1,500 W | Common high setting |
| Electric kettle | 1,200–1,800 W | Varies by market and model |
Frequently asked questions
How do I estimate a cycling appliance's daily use?
Use measured average input power when possible, or adjust runtime to represent the portion of the day the appliance actually draws power.
Can I calculate a monthly appliance cost?
Yes. Enter average watts, daily runtime, the number of days in the month, and your energy rate.
Should I use nameplate or measured watts?
Measured average input power is usually better for cycling or variable-speed equipment; nameplate power is a planning fallback.
Assumptions and limitations
- Nameplate watts may differ from average consumption.
- No standby use, duty-cycle prediction, tax, or fixed-charge model.
Method and sources
Review the electrical formulas, calculation methodology, and standards status for the references most relevant to this calculation. The broader technical sources index records source scope and verification. Last reviewed .