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Electricity Cost Calculator

Estimate an appliance's electricity cost.

Use the Electricity Cost Calculator tool

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What this electricity cost calculator does

Electricity Cost Calculator converts an appliance's wattage and running hours into kilowatt-hours, then multiplies by your price per kWh. Enter the number of days to cover a billing period, a month or a year, and the tool shows energy used and total cost.

The label wattage is often a maximum, not typical use. Devices that cycle, such as fridges and heaters, draw less on average, while older appliances may draw more. Use a plug-in energy monitor for a real figure. Tariffs with standing charges, time-of-use rates or tiered pricing are not modelled.

Why use it

  • Find out whether an old appliance is expensive to run.
  • Compare the cost of two devices before buying.
  • Estimate the effect of a device on a monthly bill.

How to use it

  1. 1Enter the appliance's power in watts.
  2. 2Enter average hours used per day and the number of days.
  3. 3Enter your price per kWh from a bill.
  4. 4Read kWh used and the total cost.

Worked examples

Heater

Input

1,500 W for 2 hours a day over 30 days

Output

90 kWh and the cost at your tariff.

Small device

Input

10 W for 24 hours a day over 30 days

Output

About 7.2 kWh, showing that low-power devices can still add up.

Common mistakes

  • Using the maximum wattage for a device that cycles on and off.
  • Confusing watts with kilowatts when entering the price.
  • Ignoring standing charges and time-of-use tariffs.

Frequently asked questions

Where do I find the wattage?
On the appliance label or power supply. If only amps and volts are given, multiply them to estimate watts.
What is a kWh?
One kilowatt used for one hour. A 1,000 W appliance running for an hour uses 1 kWh.
Does it include taxes and standing charges?
No. Enter the per-kWh rate you want to use; fixed charges are separate.
Why does my bill differ?
Real usage varies, and tariffs can change by time of day or consumption tier.

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