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Electricity Cost Calculator
Cost of running an appliance from watts and price per kWh.
100% FreeRuns instantlyNo watermark
- 1Enter detailsAdd the numbers for your scenario.
- 2CalculateVootkit updates the result instantly.
- 3ReviewCheck totals, notes and breakdowns.
Private by designProcessed on your device where possible.
Works on any deviceDesktop, tablet and mobile browsers.
No installationOpen the page and start working.
Always free coreUse the free plan for everyday tasks.
How to use Electricity Cost Calculator
Vootkit updates the result instantly.
02Check totals, notes and breakdowns.
03Copy the answer into your workflow.
04Your files stay private
Your work is processed locally in your browser where possible and is never added to a Vootkit upload library.
Learn more about privacyAlmost every guess people make about what an appliance costs to run is wrong, and wrong in a consistent direction: the things that feel expensive are cheap, and the boring ones nobody thinks about are where the money goes.
What Electricity Cost Calculator does
Multiplies watts by hours by days, converts to kilowatt-hours and multiplies by your tariff, giving the cost of running one appliance over a period.
The unit that matters is the kilowatt-hour, and the conversion trips people constantly: 100 watts for 10 hours is one kWh, not 100.
Typical draws, for comparison
| LED bulb | 8-10 W |
|---|---|
| Laptop | 30-65 W |
| Desktop PC and monitor | 150-400 W under load |
| Fridge-freezer | 100-200 W, but cycling — daily kWh is the useful figure |
| Electric kettle | 2,000-3,000 W, for two minutes |
| Electric heater | 1,500-3,000 W, for hours — this is where bills are made |
Detailed steps
- Find the wattage on the appliance label or its rating plate.
- Enter realistic hours per day, not maximum possible hours.
- Enter your actual price per kWh from a bill — not the number you half-remember.
- Compare two appliances rather than reading one in isolation. The comparison is what changes behaviour.
Worth knowing
Wattage on a label is usually the maximum draw, not the average. A fridge rated at 150 W does not use 150 W continuously — the compressor cycles, so real consumption might be a third of that. A kettle, by contrast, genuinely pulls its full 3,000 W for the whole two minutes. For anything that cycles or has a thermostat, the label overstates the cost, and a plug-in energy monitor is the only way to get the real figure.
Frequently Asked Questions
Where do I find the wattage?
On the rating plate — usually a small label on the back or underneath, sometimes moulded into the plug. If it lists volts and amps instead, multiply them: 230 V at 2 A is 460 W. Laptop and phone chargers state the output on the brick itself, which is closer to actual consumption than most appliance labels.
Why is my bill higher than these numbers suggest?
Because a bill includes a standing charge that applies whatever you use, and often a higher rate for the first block of units each day. This tool works out the marginal cost of running one thing, which is the right number for deciding whether to leave something on, and a smaller number than the bill it contributes to.
Do standby modes matter?
Less than they used to but not nothing. Modern devices draw around 0.5 W on standby, so a device left on all year costs roughly 4 kWh — pennies. Older equipment, set-top boxes and anything with a transformer can pull 10-20 W continuously, which over a year genuinely adds up.
What is a kilowatt-hour?
One thousand watts drawn for one hour, and it is the unit your supplier bills in. A 100 W bulb for ten hours is one kWh; a 2,000 W heater for half an hour is also one kWh. Getting comfortable with that conversion is most of what makes energy costs intuitive rather than mysterious.
Is Electricity Cost Calculator free?
Yes. The Vootkit free plan includes 5 tool runs a day. Upgrade to Vootkit Pro for unlimited daily use, an ad-free workspace and saved workflows.
Are my files uploaded?
No. Electricity Cost Calculator runs entirely in your browser — your file is processed on your own device and never sent to a server. There is nothing for us to store or delete.
Do I need to install anything?
No. Electricity Cost Calculator works in any modern browser on desktop, tablet or phone. Open the page and start.
How often can I use it? Is there a daily limit?
On the free plan you get 5 tool runs a day. When you reach the limit you'll see a prompt to upgrade, and it resets the next day. Vootkit Pro removes the cap entirely for unlimited daily use.
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This tool processes everything locally in your browser. You can disconnect from the internet after the page loads and it will still work.