Skip to content
Open calculators

UPS Battery Runtime and Capacity Calculator

Estimate battery runtime from usable energy and load, and estimate battery energy required for a target runtime.

Inputs

System inputs

Range: 0.1–1,000,000 kWh

Enter nominal battery energy in kWh before the usable-energy factor.

Range: 0.1–1,000,000 kW

Enter UPS output load in kW for the modeled condition.

Range: 10–100 %

Enter battery-to-load efficiency as a percent at the modeled load.

Range: 1–100 %

Enter usable fraction of nominal battery energy as a percent after reserve/derating assumptions.

Range: 0–1,000 h

Enter target runtime in hours for the required-capacity calculation.

Result

Energy-model battery capacity for target runtime (kWh)
55.56
Energy-model runtime (h)
3.60

Formula

Calculation logic

Formula definitions and substituted values.

Related calculators

Screening tool. Verify the result against the manufacturer's published rating, the actual equipment, route, floor, and applicable local requirements before ordering, installing, or relying on it.