Electrical / Power Calculator

Includes watts / amps / volts conversions, a UPS runtime estimator, and battery discharge curves. Designed as a single-file webpage for desktop and mobile browsers.

Watts / Amps / Volts Calculator

P = V × I

UPS Runtime Estimator

Battery-backed runtime

Battery Discharge Curve

Projected state of charge
Point State of Charge Approx. Voltage Elapsed Runtime

Quick Notes

Assumptions
This calculator uses simplified engineering estimates for quick planning. • Watts, amps, and volts follow the basic single-phase relationship P = V × I × PF. • UPS runtime is estimated from battery energy, UPS efficiency, and usable battery fraction. • Battery discharge curves here are planning curves, not manufacturer-certified curves. • Real-world runtimes and terminal voltages vary with temperature, battery age, discharge rate, inverter losses, and cut-off settings. • For critical systems, verify against the UPS vendor data sheet and the battery manufacturer discharge tables.

Tip: for the best accuracy, use real measured load watts, the correct battery chemistry, and actual manufacturer runtime data whenever available.

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