How to use this calculator
- Enter your electricity price in cents per kWh, or select a state benchmark and check its reference period.
- For constant power draw, enter watts and operating time. For a cycling appliance such as a refrigerator, use annual EnergyGuide kWh when available.
- Add the appliances you want to compare and adjust quantities. Review monthly and annual costs, then try an alternative annual energy-use figure.
THE CONTEXT BEHIND THE COST
Choose the right model before trusting the number.
Wattage describes power at a point in time. Energy depends on how long that power is drawn. A constant-wattage device fits the watts-times-hours model; a refrigerator that cycles on and off often does not.
For an EnergyGuide label, enter annual kWh rather than its printed annual dollars. The label’s dollar estimate uses a reference energy price. Applying your own bill rate to its kWh makes the estimate more relevant to you.
A whole-home list is a sum of the appliances you entered. It is not a complete bill forecast. Unlisted devices, standby use, fixed charges, taxes, tiered rates, and time-of-use pricing can explain the difference.
Cost examples
Space heater and annual-kWh running cost examples
All examples use the EIA U.S. residential average of 18.31¢/kWh for July 2026 and one appliance. Heater examples assume constant draw for the stated hours, 30 days per month, repeated for 12 months. The annual-label example uses 550 kWh over a whole year and divides its annual cost by 12.
| Usage example | Per month | Per year |
|---|---|---|
| 1,500 W heater · 2 hours/day | $16.48 | $197.75 |
| 1,500 W heater · 5 hours/day | $41.20 | $494.37 |
| 550 kWh/year label example | $8.39 | $100.71 |
The label example can represent a cycling appliance such as a refrigerator; 550 kWh is an editable example, not a typical-use claim. Check the device’s own label. For a heater with a thermostat, count the time it actually draws power.
A worked example
With the illustrative inputs used when this tool first opens:
Estimated appliance energy cost: $41.20 per monthSpace heater example: 1,500 W ÷ 1,000 × 5 hours × 30 days/month × 12 × 1 = 2,700 kWh/year.
Generated with the same calculation engine as the interactive result.
Formulas you can inspect
Monthly kWh = watts ÷ 1,000 × hours/day × days/month × quantity. Explicit monthly schedules are multiplied by 12 for annual results.
Weekly annual kWh = watts ÷ 1,000 × hours/day × days/week × (365.2425 ÷ 7) × quantity. Monthly average = annual ÷ 12.
EnergyGuide annual kWh = label annual kWh × quantity.
Energy cost = kWh × rate in cents ÷ 100. Household costs are summed before display rounding.
Assumptions and limits
- Example heater and EnergyGuide values come from the product’s worked examples. They are not measured device specifications or a catalog of typical appliance wattages.
- State rates are EIA residential averages for July 2026, released September 24, 2026. They are averages, not your utility tariff. Prefer a current bill.
- A 30-day monthly schedule annualizes to 360 operating days. A seven-day weekly schedule uses 365.2425 days. These are intentionally different conventions.
- Comparing an alternative shows modeled energy savings only. Purchase price, disposal, installation, service life, and manufacturing impacts are excluded.
Sources for this tool
- U.S. Energy Information Administration: Electric Power Monthly, Table 5.6.A ↗July 2026 · released September 24, 2026 · Checked
- U.S. Energy Information Administration: Measuring electricity ↗Undated reference · Checked
- Federal Trade Commission: How to use the EnergyGuide label ↗August 2022 · Checked
Common questions
How much does a 1,500-watt space heater cost to run?
At the EIA U.S. residential average of 18.31 cents per kWh for July 2026, a heater drawing 1,500 watts continuously costs $0.2747 per operating hour: 1.5 kWh × $0.1831. Five hours a day for 30 days uses 225 kWh and costs $41.20 a month. Your own rate, thermostat cycling and schedule change the answer.
Does this work as a space heater cost calculator or a dryer energy cost calculator?
Yes, for both, with different inputs. A space heater draws close to its nameplate wattage while the element is on, so enter its watts and the hours it actually runs rather than the hours it is switched on. A clothes dryer cycles and varies by load, so and dryers carry no EnergyGuide label, so use the ENERGY STAR estimated annual kWh for a certified model, or your own measured figures, instead of a constant draw. A gas dryer still uses electricity for the motor and controls; this tool prices only the electricity you enter, never the gas.
How do you calculate electricity cost?
Multiply the energy in kWh by the price per kWh in dollars. For a device rated in watts: watts ÷ 1,000 × hours used = kWh. A rate of 18.31 cents means $0.1831 per kWh; enter 18.31 in the cents field. This tool accepts annual kWh directly or calculates kWh from watts and operating time.
Are the state electricity rates my exact utility price?
No. They are dated EIA residential averages, not a utility quote. Your service area, plan, time-of-use periods, and charges can differ. Use your own variable bill rate for a more relevant appliance estimate; this model excludes fixed monthly charges.
Should I run a refrigerator at its wattage for 24 hours?
Usually that would overstate constant power draw because the compressor cycles. Use annual label kWh or a suitable electricity meter measurement when possible.
Where do I find my electricity rate?
Your bill may show a price per kWh or energy charges and kWh used. Use an all-in variable rate that matches the charges you want to model; fixed monthly charges are excluded.
Why do monthly and weekly schedules differ?
An explicit 30-day monthly schedule repeats 12 times. A weekly schedule averages over a 365.2425-day year. Choose the convention that best describes your usage.
Methodology reviewed September 5, 2026. Appliance electricity cost methodology · Report a correction