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.

Full capacity (Ah)

Rated full capacity of the battery.

Used capacity (Ah)

Charge already drawn from the battery.

Compute the depth of discharge of a battery from the charge drawn and its rated capacity. 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]

Discharge depth (%)

Percentage of rated capacity that has been removed.

• 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 Cycle Count Estimate

  Estimate full-equivalent battery cycles from total absolute charge-plus-discharge throughput divided by twice the rated ampere-hour capacity.

• Charge Current C-Rate

  Compute a safe constant-current charge rate for a battery from its capacity and a C-rate multiple.

• Battery Discharge Rate C

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