Calculate real appliance costs—not just wattage
The calculator combines appliance power, quantity, time and separate day and night tariffs.
Using a capped variable tariff? Our live October 2026 energy price cap guide explains the current 26.11p/kWh national Direct Debit average, why regional rates differ, and which rate to use in solar calculations.
Working out summer cooling costs? See how to compare appliance demand, solar timing and export opportunity cost in our guide to running air conditioning with solar panels in the UK.
Energy use
Power multiplied by operating time.
kWh = kW × Hours
Cost
Energy multiplied by the applicable tariff.
Cost = kWh × Price per kWh
Blended tariff
Weighted average of day and night rates.
Day share × Day rate + Night share × Night rate