Electricity Cost Calculator: Appliance kWh & Running Cost

Finding the wattage

The most reliable number is on the appliance itself. Look for a nameplate sticker on the back, bottom or inside the door. It usually lists watts; if it shows amps and volts instead, multiply them — a 120 V device drawing 10 A uses about 1,200 W. Chargers and electronics often list the maximum input, which can be well above what they draw in normal use.

If you can’t find a label, pick the appliance from the list and leave the wattage at 0. The calculator then uses a typical running wattage: the midpoint of the published range for most appliances, the rated figure for fixed-power devices such as a 1,500 W space heater or a 7,200 W Level 2 EV charger, and 10 W for an LED bulb. The wattage table below the results shows every range so you can judge how far off a typical value might be.

For the best accuracy, a plug-in energy meter measures actual kWh over a few days, including standby draw and cycling.

Worked example: a television

At a 35¢ rate the same TV costs about $80 a year; at 12¢, about $27. That threefold spread is why your own rate matters more than any wattage estimate. Divide your bill’s total charges by the kWh used to get it.

Appliances that cycle

Some appliances are plugged in all day but only draw full power part of the time. A refrigerator’s compressor switches on and off to hold temperature, and air conditioners, space heaters and water heaters do the same under thermostat control. The duty cycle field handles this: it is the share of time the appliance actually runs.

Take a refrigerator at the typical 550 W running 24 hours a day:

Even 40% may be high for a modern fridge. Published figures put typical refrigerator use at about 400–700 kWh a year, which works out to a much lower effective duty cycle at that wattage. If your fridge has a yellow EnergyGuide label, its kWh-per-year figure is a better starting point than any wattage estimate — enter it as a custom appliance: for example 600 kWh ÷ 365 days = 1.64 kWh a day, which is 68.5 W running 24 hours at 100%.

The big users

Appliances that turn electricity into heat draw the most power: ovens and ranges (2,000–5,000 W), clothes dryers (1,500–5,000 W), water heaters (about 4,500 W) and hair dryers (1,500–2,000 W). A hair dryer is used for minutes, so its yearly cost is small. A tank water heater or an EV charger runs for hours, which is where large bills come from.

For example, charging an EV on a 7,200 W Level 2 charger for 2 hours a day uses 14.4 kWh a day — about 5,256 kWh and $957 a year at $0.182. Central AC at 3,000–4,000 W is similar during a hot summer, which is why cooling dominates many summer bills.

Limits of a flat-rate estimate

The calculator uses one price per kWh. On a time-of-use plan, running the dryer or charging a car at night can cost far less than the same kWh in the late afternoon. Tiered plans charge more once your monthly use passes a threshold, so adding a big new load costs more than the average rate suggests. Fixed monthly customer charges don’t change with use, and they are not counted here.

Related calculators

If cooling is your biggest load, the HVAC replacement cost calculator shows how much a higher-SEER2 unit saves, and the insulation calculator shows how to cut the load at its source. To offset your whole bill, try the solar payback calculator.

How this calculator works

• kWh per day of use = watts × hours per day × duty cycle × quantity ÷ 1000.
• kWh per year = kWh per day of use × days per week × 365 ÷ 7. kWh per month = yearly ÷ 12.
• Cost = kWh × electricity rate.

Assumptions and limitations

• Preset wattages are the midpoint of EnergySage running-watt ranges, except LED bulbs (low end of the bulb range, 10 W) and fixed-rating appliances such as space heaters and Level 2 EV chargers.
• Dishwasher and water heater wattages are editorial estimates.
• A year has 365 days (52.14 weeks); a month is one-twelfth of a year.
• The rate is a flat price per kWh. Time-of-use and tiered plans make the real cost higher or lower depending on when you use power.

These results are planning estimates, not quotes. Local prices, site conditions and building codes vary, so get written estimates from licensed contractors before you commit to a budget.

Frequently asked questions

Sources and data

• EIA Short-Term Energy Outlook (Sept 2026) — elec coal renew.php
• EnergySage — house watts

Prices are US national ranges reviewed October 2026 (data version 2026.10). A few values are editorial estimates where no single published source exists; the Cost Index marks each one. Read our methodology and editorial policy.