Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Initial capacity (Ah)

Required number input.

Current capacity (Ah)

Required number input.

Calculate capacity loss as a percentage of initial battery capacity, using measurements at comparable discharge rate and temperature. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Capacity fade (%)

The resulting capacity fade returned as a number.

• Battery capacity, state of charge, runtime, and aging depend on chemistry, temperature, discharge profile, cutoff voltage, cell balance, charge method, rate capability, self-discharge, and prior history. Nominal amp-hour or watt-hour ratings do not guarantee usable energy under every load.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Battery State Of Health

  Calculate battery state of health as measured full-charge capacity divided by rated new capacity, expressed as a percentage; values over 100% can be valid measurements.

• Battery Discharge Rate C

  Battery discharge C-rate from current and rated ampere-hour capacity.

• Battery Remaining Capacity

  Calculate remaining battery charge in ampere-hours from measured full-charge capacity and state of charge percentage.