Electricity Cost Calculator Calculators
What an appliance actually costs to run, per day, month and year.
Electricity Cost Calculator is a free online tool that what an appliance actually costs to run, per day, month and year. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Calculators
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 5
- Works offline
- Yes, after the first visit
About Electricity Cost Calculator
Cost is watts ÷ 1000 × hours × price per kWh. The figures surprise people in both directions: a 2kW heater run four hours a day costs a serious amount over a winter, while a 5W device left on permanently costs a few pounds a year. Standby loads matter mostly in aggregate.
How to use it
- Enter power, hours used per day and price per kwh.
- Adjust the remaining 2 settings if the defaults do not fit your case.
The 5 settings
| Setting | What it does | Default |
|---|---|---|
| Power | A numeric value. | 1200W |
| Hours used per day | Range 0–24. | 2 |
| Price per kWh | A numeric value. | 0.28 |
| Days per week used | Range 1–7. | 7 |
| Currency | Choose from 7: USD $, GBP £, EUR €, INR ₹, AUD A$, CAD C$…. | USD $ |
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
| Controls | Power, Hours used per day, Price per kWh, Days per week used, Currency |
Questions
Where do I find the wattage of an appliance?
On the rating label, usually on the back or underneath, or in the manual. Note that many appliances draw their rated power only intermittently — a fridge cycles, so its average draw is far below its peak.
What does the currency option change?
It offers 7 choices — USD $, GBP £, EUR € and INR ₹ and more. The default is USD $, which suits most cases; change it when your input or your destination calls for something specific.
What are the limits on hours used per day?
It accepts 0 to 24, starting at 2. The other numeric controls have their own ranges: days per week used 1–7.
Is the arithmetic exact?
It uses double-precision floating point — about 15 significant figures, far more than the inputs justify. Displayed rounding is cosmetic; the underlying numbers are not rounded between steps, so chained results do not drift.