Electricity Cost Calculator

This electricity cost calculator converts an appliance’s power and running time into energy, kWh = watts × hours ÷ 1,000, and multiplies it by your price per kilowatt-hour. It shows the energy and cost per day, month and year, and the cost of one hour of use.

Reviewed by CostPulse HubLast updated

Appliance and use

Imperial units
W
On the label or in the manual. 1 kW = 1,000 W.
h
per kWh
Published average: EIA 2026 forecast, STEO Oct 2026The unit rate on your bill.
Example prices: US (USD) — edit to match your area

Starting prices for the United States in USD. Fields marked “Published average” use the source below, at the date of that source. All other starting prices are example prices: round planning values, not quotes or averages. Prices change by store, area and season, so edit them to match your area. Electricity: U.S. average residential price forecast for 2026, 18.2 cents per kWh, EIA Short-Term Energy Outlook, October 2026 (source).

Your estimate

Results update as you type.

Cost per month
$24.91
Cost per year
$298.94
Cost per hour of use
$0.27
Energy per day of use
4.5 kWh
Energy per month
136.9 kWh
Energy per year
1,642.5 kWh

How to use the electricity cost calculator

  1. Find the appliance’s power in watts on its rating label, in the manual or on the plug adapter. If it shows kW, multiply by 1,000.
  2. Enter how many hours a day it runs and on how many days a week.
  3. Enter how many identical appliances you are working out, such as several light bulbs or fans.
  4. Type the unit rate per kWh from your electricity bill. For the US, UK and the EU the field starts with a published average.
  5. Read the monthly and yearly cost, and compare appliances by running the calculator for each.

How the cost is worked out

kWh per day of use = watts × hours × quantity ÷ 1,000
kWh per year = kWh per day × days per week × 52.14
Cost = kWh × price per kWh; cost per hour = watts × quantity ÷ 1,000 × price

A kilowatt-hour is the energy used by a 1,000 W appliance running for one hour, and it is the unit on every electricity bill. A year is taken as 365 ÷ 7 = 52.14 weeks, and a month as a twelfth of a year.

Worked example

A 1,500 W space heater used 3 hours a day, every day, with electricity at 18.2 cents per kWh:

  1. Energy per day: 1,500 × 3 ÷ 1,000 = 4.5 kWh.
  2. Per year: 4.5 kWh × 7 days × 52.14 weeks = 1,642.5 kWh, or 136.9 kWh a month.
  3. Cost: $24.91 a month, $298.94 a year, and $0.27 for each hour it runs.

Load this example into the calculator

Tips and common mistakes

  • The label shows the maximum. Heaters, fridges, freezers and air conditioners switch on and off with a thermostat, so their real use is often well below watts × hours. Treat the result as an upper estimate for them.
  • Standby adds up. TVs, consoles and chargers draw a few watts all day. Enter the standby watts with 24 hours a day to see what that costs.
  • Use your real tariff. Time-of-use, tiered and night-rate plans charge different prices at different times; use the rate for the hours the appliance runs.
  • Measure if unsure. A plug-in energy meter shows the actual kWh an appliance uses over a week.
  • Compare before replacing. Running the old and the new model through the calculator shows the yearly saving, which you can weigh against the price of the new appliance.

US, UK and Canada differences

US electricity prices vary widely between states, and the starting value is the EIA’s national average forecast for 2026. In Great Britain, most households on standard tariffs pay a unit rate limited by Ofgem’s price cap, which changes every quarter, plus a daily standing charge that this per-appliance calculator leaves out. Canadian rates differ greatly between provinces, from low hydro-based prices to much higher ones, so the CAD value is only an example; your bill has the real rate.

Metric units and other countries

Watts and kilowatt-hours are the same everywhere, so this tool needs no unit change. In Pakistan, India and other countries with slab-based tariffs, the price per unit rises as monthly use goes up; use the rate for the slab your household usually reaches, and remember that fixed charges and taxes are extra.

Frequently asked questions

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Results are estimates for planning only. Get written quotes from licensed contractors, check product labels, and follow your local building codes. See our disclaimer.