Electricity Cost Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the appliance's power in watts, how many hours a day it runs, and your electricity rate in $/kWh.
- Press Calculate to see the running cost per day, week, month and year.
How it works
Energy in kWh per day = power (watts) ÷ 1000 × hours. The cost is that energy times your rate, then scaled to week (×7), month (×30.44) and year (×365.25).
Worked example
A 1000 W heater, 5 h/day at $0.30/kWh. 5 kWh/day = $1.50/day ≈ $10.50/week, ≈ $547/year.
Frequently asked questions
Where do I find the power in watts?
On the appliance's rating label or manual. For something rated in amps, watts ≈ volts × amps (e.g. 240 V × 4 A = 960 W).
What rate should I use?
Your usage (per-kWh) rate from your electricity bill. Many bills also have a daily supply charge that this tool doesn't include.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.