Electricity Cost Calculator

Enter the power and daily use of each appliance, the number of days and your price per kWh to estimate the energy used and the cost.

Appliances (1 to 10 rows; the name is optional; only rows with a power and hours of use are calculated)

Power is the rating on the appliance, in watts (1 kW = 1,000 W). The quantity is how many of the same appliance you have (empty = 1).

Number of days (1 to 366)

days

Price per kWh (take it from your bill or tariff)

per kWh

This tool does not include any price. Electricity prices differ by provider, plan, time of day and usage, so enter your own. The currency is up to you; the result is in the same currency.

Rounding of the cost (to 2 decimal places)

Estimated electricity cost —

Energy used (total)—

Energy used per day—

Cost per day—

Energy used by each appliance

—

This is a simple estimate. A real bill can include fixed charges, taxes, tiered or time-of-use rates and plan discounts, which are not included. Take the price per kWh from your bill or tariff.

The number copied is the cost, without commas.

How it is calculated

Energy (kWh) = power (W) × quantity × hours of use per day × number of days ÷ 1,000.
Cost = energy × price per kWh. The cost is rounded to 2 decimal places once, at the end, on the total of all appliances.
The cost per day is the total energy per day times the price, shown to 2 decimal places.

The calculation uses exact fractions and whole numbers. The money is held in hundredths, so there is no floating-point error. The cost is rounded only once, and in the way you choose.

Example

An appliance of 1,000 W used 2 hours a day, and one of 150 W used 8 hours a day, for 30 days, at 0.15 per kWh (example numbers only):

First: 1,000 × 2 × 30 ÷ 1,000 = 60 kWh
Second: 150 × 8 × 30 ÷ 1,000 = 36 kWh
Total: 96 kWh; cost = 96 × 0.15 = 14.40
Per day: 3.2 kWh and 0.48

Notes

Many appliances do not draw their rated power all the time. A rating is a maximum or typical figure on the label; enter the average power you expect if you know it.
A kilowatt-hour is 3.6 MJ. To convert other energy units, use the Energy Converter. For the relation between volts, amps and watts, see the Ohm's Law Calculator.
Tiered or time-of-use rates need a separate calculation for each part of the usage.

Sources

This is a general calculation: energy is power times time, and cost is energy times price. No source was checked for it, and no tariff is used.

Frequently asked questions

How do I calculate the electricity cost of an appliance?

Multiply its power in kilowatts by the hours of use and the days to get kWh, then multiply by your price per kWh.

How many kWh does a 1,000 W appliance use in an hour?

1 kWh.

Does the tool include taxes and fixed charges?

No. Only energy times price. Add your own fixed charges and taxes.

Which currency does it use?

Any. Enter the price in your currency and the cost is in the same currency.