Cost per kWh Calculator: Bill Rate & Appliance Cost

Work out what you really pay per kWh (per unit) from your electricity bill, then see what any appliance costs to run at that price. Everything runs in your browser and nothing you type is sent anywhere.

Quick answer: your average cost per kWh = total bill ÷ units used. The price of each extra unit = (total bill − fixed charges) ÷ units used. For example, a bill of 6,000 for 200 units, with 500 of fixed charges, averages 6,000 ÷ 200 = 30 per kWh. Excluding the fixed charge, each unit costs (6,000 − 500) ÷ 200 = 27.5. Use the second figure to price an appliance only if your tariff has no slabs; otherwise check the slab table on your bill.

1. Cost per kWh from your bill

Total bill amount

Any currency.

Units used (kWh)

Printed on the bill as units or kWh.

Fixed charges (optional)

Standing, meter or service charge, if listed.

Enter the bill amount and the units used.

2. Cost to run an appliance

Appliance power (watts)

Hours per day

Days

Price per kWh

Leave blank to see units only.

Enter the watts and hours to see the result.

How the calculation works

Cost per kWh = (total bill − fixed charges) ÷ units used. With no fixed charge entered, the result is your average cost per unit, which includes any fixed charges, taxes and slab effects. Appliance cost = watts ÷ 1,000 × hours × days × price per kWh. One electricity unit on a bill is one kilowatt-hour.

For the full method behind appliance units, read how to calculate appliance electricity cost.

Worked example

Bill: 6,000 for 200 units, with a fixed charge of 500.
Average cost per kWh = 6,000 ÷ 200 = 30.
Price of each extra unit, excluding the fixed charge = (6,000 − 500) ÷ 200 = 27.5.
A 1,500 W heater for 3 hours a day over 30 days uses 1.5 × 3 × 30 = 135 units. At 27.5 per unit that is 135 × 27.5 = 3,712.5.

The figures are invented teaching values, not a real tariff. Use the numbers from your own bill.

Slab and time-of-use tariffs: where the price per unit rises with monthly use, or changes by time of day, one cost per kWh is only an average. Extra appliance use may be charged at your top slab, so the true cost of an appliance can be higher than the average price suggests. Check the slab table on your bill.

Common questions

Where do I find my kWh price?

Look for a rate per unit or per kWh on your bill or your supplier's tariff page. If only a total is shown, section 1 gives an average from the total and the units used.

Why is my average price higher than the listed rate?

Fixed charges, taxes, levies and adjustments are spread across your units, which raises the average.

Is a unit the same as a kWh?

On almost every bill, yes. One unit means one kilowatt-hour.

Related guides

Educational estimate only. It does not include taxes, tariff adjustments or start-up surges. Updated 10 November 2026 · Climate Calculator.