Battery State of Charge Calculator

How Battery State of Charge works

The result comes from SoC = remaining ÷ full capacity × 100. Battery State of Charge uses Remaining capacity, Usable full capacity to report State of charge.

With the loaded values, state of charge evaluates to 80.00%. Change only the quantity being investigated. Use Battery Self-Discharge Calculator.

Inputs for Battery State of Charge

Remaining capacity and Usable full capacity belong to Battery State of Charge. Keep source units with remaining capacity.

Treat the preset entries as an arithmetic example. Supply measurements or ratings from the actual circuit. Compare this result with Battery Specific Power Calculator when specific power is also needed.

Remaining capacity

Example entry: 72 Ah.

Usable full capacity

Example entry: 90 Ah.

Reading the Battery State of Charge result

This output represents Battery State of Charge.

Standard size, duty, temperature, and transient checks remain outside this single equation.

Measurement and units

Battery calculations depend on chemistry, temperature, age, discharge rate, and the limits of the battery management system. Check prefixes on remaining capacity. For bank capacity, use Battery Bank Capacity Calculator.

Scenario differences are meaningful only with consistent units and observation points.

Limits of this calculation

Voltage alone may not indicate state of charge under load. Continue to Depth of Discharge Calculator for depth of discharge.

The arithmetic is intentionally narrower than a complete circuit model. Unentered effects remain outside Battery State of Charge.

Questions about Battery State of Charge