⚡ Electricity Cost Calculator
Find how much your appliances cost to run per day, month and year. Add devices by watts and hours, use your own rate, and see which one costs most.
Find it on your bill: total charges ÷ kWh used gives your all-in rate. 17¢ is only an example — rates vary a lot by state and utility.
Devices
Preset wattages are typical figures. Check the label (watts, or volts × amps) or measure with a plug-in energy meter for your exact device.
| Device | kWh/day | Per month | Share |
|---|---|---|---|
| Space heater | 6.00 | $30.60 | |
| Desktop computer | 0.90 | $4.59 |
What Electricity Cost Calculator Does
This electricity cost calculator shows what your appliances cost to run per day, month and year. Add devices from a list of common appliances or enter your own, set how many watts each draws and how many hours a day it runs, and enter the rate from your electric bill. A breakdown shows each device’s monthly cost and its share of the total, so the biggest users stand out.
Preset wattages are typical figures to get you started — the real number for your device is on its label or power adapter, or can be measured with an inexpensive plug-in energy meter. Devices that cycle on and off, like refrigerators, are listed with an average draw rather than their peak rating.
How to Use Electricity Cost Calculator
- Enter your electricity rate in cents per kWh from your bill
- Add devices from the list or as custom entries
- Set each device’s watts, hours per day and quantity
- Read the daily, monthly and yearly cost
- Check the breakdown to see which device costs the most
Formula Used by Electricity Cost Calculator
Energy and cost
kWh = watts × hours ÷ 1,000 · cost = kWh × rate
Worked example
A 1,500 W space heater running 4 hours a day at 17¢ per kWh.
- 1,500 × 4 ÷ 1,000 = 6 kWh a day
- 6 × $0.17 = $1.02 a day
- $1.02 × 30
Result: About $30.60 a month.
Watts from the label
Watts = volts × amps
Worked example
A label reading 120 V, 2.5 A.
- 120 × 2.5
Result: 300 W maximum — actual use is often lower.
What One kWh Runs
Approximate running time for one kilowatt-hour at each power draw.
| Device power | Time to use 1 kWh |
|---|---|
| 10 W (LED bulb) | 100 hours |
| 50 W (laptop) | 20 hours |
| 100 W (TV) | 10 hours |
| 1,000 W (window AC) | 1 hour |
| 1,500 W (space heater) | 40 minutes |
| 3,000 W (clothes dryer) | 20 minutes |
How to Read Your Result
Finding your real rate
The advertised energy rate is only part of the bill. Divide the total amount charged by the kWh used to get the all-in rate, which includes delivery, taxes and fixed fees. If you are on a time-of-use plan, use the rate for the hours the device actually runs.
Standby power
Many devices draw a few watts even when “off”: cable boxes, game consoles in rest mode, chargers and smart speakers. A few watts around the clock adds up — 5 W for a year is about 44 kWh. A switched power strip cuts it to zero.
Limitations & Accuracy Notes
- Preset wattages are typical, not measured; real devices vary.
- Heating, cooling and appliances with thermostats cycle on and off, so hours of actual running time are lower than hours switched on.
- Tiered and time-of-use rates are not modeled; use an average rate.