Energy

Electricity Cost Calculator

Enter an appliance’s power, how long it runs, and your electricity rate to estimate daily, monthly, and yearly energy use and cost. Switch to multiple-appliance mode to total up a whole room or home. An estimate for planning — not your exact bill.

Last updated: September 30, 2026

Your inputs

Results update instantly as you type.

Calculator mode

One appliance, or several added together.

Appliance power(W)

Rated power from the appliance label or manual. Example: a ceiling fan is often around 75 W.

Quantity

How many identical appliances run the same hours.

Appliances

Add each appliance with its own power and daily hours. Example rows are pre-filled — edit or remove them.

Appliance 1

Name

Watts(W)

Qty

Hours/day(h)

Appliance 2

Name

Watts(W)

Qty

Hours/day(h)

Hours per day(h)

Average running hours in a typical day.

Days per month

Billing-month length. 30 is a good average.

Electricity rate(per kWh)

Your price per kilowatt-hour, from your bill. Example: 8.10.

Currency

Changes display only — it does not look up your local tariff.

Your result · Monthly electricity cost

₹240.00

Monthly energy: 30kWh
Daily cost: ₹8.00
Annual cost: ₹2,880.00

Daily energy: 1kWh
Annual energy: 360kWh

Free · No signup · Math stays in your browser

What your result means

Monthly electricity cost is the headline: what the entered usage adds to a 30-day period at your rate. Monthly energy beside it shows the same answer in kilowatt-hours, the unit your meter and bill use.

Daily figures help you judge single habits (leaving a heater on), while annual figures assume the month repeats — useful for comparing appliances, not for predicting a full year.

How the calculation works

Convert watts to kilowatts and multiply by quantity and daily hours to get each day’s energy.
Multiply daily energy by days in the month, and by twelve for the yearly view.
Multiply each energy figure by your per-kWh rate to get its cost. In multiple-appliance mode the daily energies are added first.

Formula

daily kWh = watts × quantity × hours ÷ 1000; monthly kWh = daily × days; cost = energy × rate

Daily energypower (W) × quantity × hours/day ÷ 1000
Monthly energydaily energy × days/month
Annual energymonthly energy × 12
Costenergy × electricity rate

Worked examples

Example: 1,000 W heater, 4 h/day, 30 days at 8.10/kWh
mode: singlepowerWatts: 1000quantity: 1hoursPerDay: 4daysPerMonth: 30rate: 8.1currency: INR
Result: Daily energy 4 · Monthly energy 120 · Annual energy 1,440 · Daily cost $32.40 · Monthly electricity cost $972.00 · Annual cost $11,664.00
Example: fridge + fans for a month at 8/kWh
mode: multipledaysPerMonth: 30rate: 8currency: INRappliances: 2 items (Refrigerator, Ceiling fan)
Result: Daily energy 5.4 · Monthly energy 162 · Annual energy 1,944 · Daily cost $43.20 · Monthly electricity cost $1,296.00 · Annual cost $15,552.00

Assumptions

What this calculation takes for granted — check these before relying on the result.

Assumptions:

Default values are an example starting point — replace them with your appliance figures.
Power draw is treated as constant while running; real devices cycle (e.g. fridge compressors).
One flat rate applies to all energy; time-of-use and slab differences are not modelled.
Annual figures repeat the month twelve times — seasonal usage is not modelled.
Currency selection changes display only; it does not fetch tariffs.

Limitations

Why your real figure may differ:

This is an energy-cost estimate, not your bill: fixed/demand charges, taxes, fuel surcharges, and subsidies are excluded.
Slab or tiered tariffs charge different rates at different usage levels — a single rate under- or over-states those bills.
Time-of-use plans bill peak and off-peak hours differently; average hours miss that split.
Standby draw, voltage fluctuation, and appliance ageing shift real consumption.

Frequently asked questions

What is electricity consumption?

The amount of electrical energy a device uses over time. Power (watts) is the rate of use; consumption is power sustained over hours — that is what you pay for.

What does kWh mean?

A kilowatt-hour is 1,000 watts used for one hour. A 100 W bulb burning for 10 hours consumes 1 kWh. Meters and bills measure in kWh.

How is my electricity cost calculated?

Energy (kWh) × your per-kWh rate. This calculator first finds daily kWh from watts, quantity, and hours, scales to month and year, then multiplies by your rate.

Why is my actual bill higher than this estimate?

Bills add fixed charges, demand charges, taxes, fuel surcharges — and subtract subsidies — on top of energy cost. Slab tariffs and time-of-use rates also differ from a single flat rate.

What are time-of-use rates?

Tariffs that price peak-hour electricity higher than night or off-peak hours. Shifting heavy appliances off-peak can cut bills under such plans; this calculator uses one average rate.

Does changing the currency update my tariff?

No. Currency only changes how the result is displayed. Your rate always comes from your own bill — the tool never looks up local prices.

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