kWh cost calculator
Turn a known energy usage figure — from a smart meter, an appliance's energy label, or a bill — into a cost, using your electricity price.
Result
Cost
How to use this tool
- Enter the energy used, in kWh — from a smart meter reading, a bill, or an appliance's stated energy use.
- Enter your electricity price per kWh.
- Read the cost.
Assumptions
- Uses your entered electricity price per kWh as a flat rate, displayed in GBP (£); no live tariff lookup or currency conversion is applied. It does not model time-of-use or tiered tariffs.
Technical details: what the fields mean
- Energy used
kwhUsed - Energy used, in kilowatt-hours — the unit your electricity bill and meter both use.
- Electricity price
pricePerKwh - Your electricity price per kWh, from a recent bill or your tariff's rate.
Methodology
Cost = energy used (kWh) × price per kWh — a direct multiplication.
Worked example
150 kWh at 27p/kWh
Inputs: Energy used: 150 kWh, Electricity price: £0.27/kWh
Result: £40.50
Practical guidance
- Use your smart meter's in-home display or app to read actual kWh usage for a specific period, then apply your tariff rate here.
Common mistakes
- Using a different period's usage figure against the wrong tariff rate — check both are for the same billing period if comparing to an actual bill.
FAQs
How do I convert kWh to cost?
Multiply the kWh figure by your price per kWh — this calculator does that directly.
Last reviewed: 2026-10-11
A direct multiplication using your entered rate, displayed in GBP (£) with no currency conversion — it does not account for standing charges, VAT, or tiered/time-of-use tariff structures that some suppliers use.
This tool provides an indicative estimate, based on the assumptions stated above.
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