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.

Stored Watt Hours (Wh)

Required number input.

Input Watt Hours (Wh)

Required number input.

Energy efficiency of a charge cycle from measured energy stored and energy drawn from the charger. 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]

Efficiency Percent (%)

The resulting efficiency percent 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.

• Charger Efficiency

  Calculate charger energy efficiency as delivered battery energy divided by input energy over the same charging interval, expressed as a percentage.

• Battery Stored Energy Calculator

  Convert a battery charge rating into stored energy, Wh = V * Ah, so packs of different voltages can be compared on equal footing.

• Capacity From Energy

  Convert stored energy in watt-hours to amp-hour capacity at a nominal pack voltage.