Electric vehicle charging cost calculator

Enter usable battery capacity, the starting and target charge percentages, your electricity price and charging losses. Use a loss estimate relevant to the charger and conditions. The result is especially useful for comparing home and public energy rates for the same charge.

Formula

Battery energy added = capacity × (target percentage − starting percentage) ÷ 100. Grid energy = battery energy ÷ (1 − loss percentage ÷ 100). Charging cost = grid energy × price per kWh.

Worked example

Charging a 60 kWh usable battery from 20% to 80% adds 36 kWh. If 10% of electricity drawn is lost, the grid supplies 36 ÷ 0.9 = 40 kWh. Apply your tariff to those 40 kWh.

What the result means

Grid energy is the amount relevant when electricity is billed at the charging point. Battery energy is the amount added to storage; the difference represents the selected charging losses.

Electricity price · United Kingdom

£0.2611/kWh is Ofgem’s average capped electricity unit rate for standard variable tariffs paid by Direct Debit in England, Scotland and Wales, valid from 1 July to 30 September 2026. It includes 5% VAT and excludes the separate standing charge. It is not an average across all contracts and does not apply to Northern Ireland. Use your own tariff where available.

Last reviewed: 9 September 2026 · Ofgem · July–September 2026

Enter the unit rate including any applicable tax. Check your bill rather than adding a tax percentage automatically. Standing charges, export payments and subscription fees are separate. Ofgem information applies to Great Britain; Northern Ireland has its own regulator and market arrangements.

Assumptions and limits

Battery condition, temperature, preconditioning and charger efficiency can change actual consumption. Session fees, parking charges, subscriptions and time-based charging are not included.

Questions answered

Methodology · Report an error