Energy cost calculator
Uses – kWh per month. *Per year assumes the same use every month. The rate starts at 18¢, close to EIA’s 2026 U.S. average; change it to the rate on your bill.
Affiliate note: As an Amazon Associate, The Low Bill Home earns from qualifying purchases. Buying through our links costs you nothing extra. We have not tested every product hands-on: picks are based on the makers' published specs, official energy-saving guidance and long-term buyer feedback, and we say where a product falls short.
How to use it
- Choose an appliance, or pick “Enter your own wattage” and type the watts from the label.
- Enter how many hours a day it runs and how many days a month.
- Enter your rate in cents per kWh. It starts at 18¢, close to EIA’s 2026 U.S. average, but your bill is what counts.
Where to find the numbers
Your electricity rate
Divide the total on your electric bill by the kWh used that month. That gives your all-in price, delivery charges included. To compare states, see EIA’s average residential price by state.
The appliance’s watts
Look on the label or nameplate, usually on the back or bottom, or in the manual. If it only lists amps, multiply amps by 120 (the standard U.S. outlet voltage) for a rough maximum wattage. The label shows the maximum; many appliances use less most of the time.
Most accurate: measure it. A plug-in meter like the P3 Kill A Watt EZ shows the real draw and the cost over time. Do not use one on space heaters, which should always plug straight into the wall.
Typical wattages
These are typical figures for common models. Yours may differ, so check the label.
| Appliance | Typical watts | Cost per hour at 18¢ |
|---|---|---|
| Space heater, high | 1,500 | 27¢ |
| Space heater, low | 750 | 13.5¢ |
| Window air conditioner | 500–1,400 | 9–25¢ |
| Dehumidifier | 300–700 | 5–13¢ |
| Gaming PC while gaming | 250–500 | 4.5–9¢ |
| Slow cooker on low | about 200 | 3.6¢ |
| Heated blanket | about 100 | 1.8¢ |
| 55-inch LED TV | 60–100 | 1–2¢ |
| Laptop | 30–65 | under 1.2¢ |
| LED bulb (60 W equivalent) | 8–10 | under 0.2¢ |
The formula behind it
Watts ÷ 1,000 × hours × price per kWh = cost. For example, a 100-watt heated blanket for 8 hours: 0.1 × 8 × $0.18 = 14.4¢ a night.
Related guides
- How much it costs to run a space heater, and when it beats central heat
- Phantom power: the devices that drain electricity when they are “off”
- 20 ways to lower your heating bill this winter
Affiliate Disclosure: The Low Bill Home is a participant in the Amazon Services LLC Associates Program. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Product details and availability change, so check the listing before you buy.
