Calculatium

Battery Charging Time Calculator

Estimate battery charging time from capacity, starting and target charge, charging power and efficiency using a constant-power energy model.

Enter your values

The starting values are editable examples. Results update when you change your inputs.

Example: 1,000
Allowed range: 0 – 100
Allowed range: 0 – 100
Example: 200
Allowed range: 0 – 100

Your result

Updates as you change your values.

Enter values to calculate.

How it is calculated

Energy to store = nominal Wh × (target charge − starting charge) / 100. Time in hours = energy to store / (charging watts × efficiency/100).

Worked example

A 1,000 Wh battery charged from 20% to 80% must store 600 Wh. At 200 W and 90% efficiency, the model gives about 3.33 hours.

Before you calculate

Use nominal energy in watt-hours and charging power in watts, not the charger current alone. Efficiency represents the share of input energy stored. The target charge must not be lower than the starting charge; equal values give zero additional charging time.

Interpreting the result

Actual chargers often reduce power near full charge. Temperature, battery management, simultaneous loads and charger limits can extend the duration. This estimate does not determine safe charging settings or replace the equipment instructions.

Use the units shown beside each field. Monetary fields labelled EUR stay in euros; changing language does not exchange currencies. Results are estimates under the stated assumptions.