Electricity Cost Calculator
Electricity Cost Calculator. Free, instant, no signup. Results update as you type.
Monthly cost
$37.80
- Energy per day 4.500 kWh
- Cost per day $1.26
- Energy per month 135.00 kWh
- Cost per year $459.90
- Energy per year 1,643 kWh
- Cost per hour of use $0.4200
A constant draw at the rated wattage. Motors and heating elements cycle rather than running flat out, so a fridge rated at 150W uses far less than 150W continuously. Standby draw is excluded.
How to use this calculator
- Enter power rating (watts) — The calculator loads with a worked example already filled in, so you can see what a realistic set of figures looks like before replacing them with your own.
- Fill in the remaining fields — Every field has a sensible default. Change the ones that apply to you and leave the rest.
- Read the result — The answer updates as you type — there is nothing to submit. The rows beneath the headline show how it breaks down.
- Expand the schedule — Where a year-by-year table is offered, open it. The breakdown over time usually shows something the single headline figure does not.
- Share or print — Use the share button to copy a link with your figures already filled in, or print the result — the print stylesheet strips the navigation and adverts.
What this calculator works out
To use the Electricity Cost Calculator, enter your power rating (watts), hours used per day and days per month used. The result — monthly cost — updates as you type, with no button to press and nothing to submit. The calculation runs entirely in your browser, so the figures you enter are never sent anywhere.
How this is calculated
The electricity cost calculator applies its formula to the values you enter and returns the result immediately.
A worked example
Take the values this page loads with:
- Power rating (watts): 1,500
- Hours used per day: 3
- Days per month used: 30
- Price per kWh: $0.28
On those figures the monthly cost is 37.80. Broken down:
- Energy per day: 4.500 kWh
- Cost per day: 1.26
- Energy per month: 135.00 kWh
- Cost per year: 459.90
- Energy per year: 1,643 kWh
Change any field above and every figure here recalculates — these numbers are produced by the same formula the calculator runs, so they cannot drift apart from it.
What the figures mean
The headline figure answers the immediate question. These are the ones worth paying attention to:
- Cost per year — the figure worth watching when you change your inputs.
Where a schedule is shown, expand it: the year-by-year breakdown usually reveals something the single headline number hides.
What this calculator assumes
A constant draw at the rated wattage. Motors and heating elements cycle rather than running flat out, so a fridge rated at 150W uses far less than 150W continuously. Standby draw is excluded.
Why it runs in your browser
Every calculation on this page is arithmetic, and arithmetic does not need a server. Running it locally means the result is instant, it keeps working if your connection drops, and — the part that matters — your salary, your debts and your medical measurements are never transmitted to us. There is no figure on our side to store, log or lose.
Where this calculator stops
A calculator applies the rules it is given to the figures you enter. It cannot see the rest of your circumstances, and real financial decisions are rarely decided by a single number.
Treat the result as a starting point for a conversation — with a lender, an accountant or an adviser — rather than as an answer. Where an institution will quote you a real figure, that figure is the one that counts: it will include fees, your credit profile and terms this page knows nothing about.
Keeping the figures current
The formula behind this page does not change, but the assumptions you should bring to it do — interest rates, inflation and market returns all move. Revisit the inputs rather than trusting a figure you calculated a year ago.