EV charging planner

Estimate energy and time for a battery charge change from capacity, efficiency and average input power.

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Usable battery capacity (kWh)

Starting charge (%)

More inputs and assumptions

Target charge (%)

Assumed charging efficiency (%)

Average input power (kW)

Answer

…

Estimate energy and time for a battery charge change from capacity, efficiency and average input power.

More results

Precision and calculation record

Decimal places in numeric results and text downloads

Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

Saved scenario

Save the current answer, then change an input to compare. This clears when you leave.

Formula and assumptions

Stored energy = capacity × charge change; supply energy = stored/efficiency; time = supply energy/average kW. Use average power including taper, not merely the charger’s peak rating. No vehicle charging curve or connector compatibility is inferred.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-26

Using EV charging planner

Estimate energy and time for a battery charge change from capacity, efficiency and average input power.

Next: Electric vehicle charging cost calculator

A worked example

Example inputs: usable battery capacity (kwh) = 60, starting charge (%) = 20, target charge (%) = 80, assumed charging efficiency (%) = 90, average input power (kw) = 10. Energy drawn from supply (kWh) = 40.

Before you use the result

Example results for usable battery capacity (kwh)

These examples use Starting charge (%): 20; Target charge (%): 80; Assumed charging efficiency (%): 90; Average input power (kW): 10. They are reference calculations, not recommended settings.

Usable battery capacity (kWh)	Energy drawn from supply (kWh)
30	20
60	40
120	80

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