Electricity Cost Calculator
What any appliance costs to run — per day, month, and year, from watts and your kWh rate
On the label or power brick
US average ≈ 16–17¢; on your utility bill
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Quick summary
Cost = watts × hours ÷ 1,000 × rate. A 1,500W space heater running 4 hours a day at 16.5¢/kWh costs about $1 a day — $30 a month, which surprises most people. The presets cover common appliances; the big lesson is that heat-producing devices (heaters, dryers, water heaters) dominate bills while electronics barely register: that gaming PC costs more than your TV, but the space heater costs more than five gaming PCs.
Reviewed by Simple Calculators TeamLast reviewed
How to use this calculator
- Enter the inputs requested by the calculator.
- Choose the units or options that match your situation and review the assumptions.
- Run or update the calculation to see the result.
- Review the result, breakdown, and formulas shown on the page.
- Check the inputs, units, dates, and limitations before saving or sharing the result.
Frequently asked questions
How do I calculate an appliance's electricity cost?
Watts × hours per day ÷ 1,000 gives daily kWh; multiply by your rate. A 100W TV for 5 hours is 0.5 kWh — about 8¢/day at 16.5¢/kWh. Your exact rate is on your utility bill; the US average runs 16–17¢/kWh with wide state variation (Hawaii 40¢+, Washington ~11¢).
What uses the most electricity in a home?
Heating and cooling dominate (40–50% of typical bills), then water heating (~15%), then the always-on fleet: refrigerator, dryer, lighting. Anything that makes heat from electricity — space heaters, dryers, ovens — draws 10–30× more than electronics.
How much does a space heater cost to run?
At 1,500W and 16.5¢/kWh: 25¢/hour. Eight hours a day for a winter month is about $60 — often more than the equivalent central-heat cost for one room. They're best for brief, targeted use.
Do devices use power when off?
Yes — standby (phantom) load: TVs, consoles, chargers, and anything with a remote or clock draw 1–15W continuously. A household's phantom load commonly totals 5–10% of the bill; smart power strips or switching off at the outlet eliminates it.
Key terms
- kWh
- Kilowatt-hour — 1,000 watts for one hour; the unit your utility bills.
- Nameplate Wattage
- The maximum draw on the label — cycling appliances average below it.
- Phantom Load
- Standby power drawn by devices that are 'off.'
- Time-of-Use Rates
- Utility pricing that varies by hour — running dryers and EV charging off-peak can cut their cost 30–50%.
Methodology, sources & limitations
This page shows the formula, assumptions, and limitations used for this estimate. Rates, thresholds, and other time-sensitive inputs can change, so verify them against the relevant official source before relying on a result.
For our review approach and the primary sources we consult, see the methodology and source policy. If you spot an outdated figure or formula, please contact us with a correction.