Sam Gorman

Find resistor power in watts, add safety headroom, and choose the first wattage rating that fits your parts list.

Find watts, amps, or volts from two known values for DC, single-phase AC, or three-phase AC with power factor.

Add watts from battery-backed equipment and check a UPS against its W and VA ratings.

Estimate UPS runtime from load watts, battery volts, Ah, series and parallel counts, efficiency, health, and losses.

Estimate generator running watts with start-up load, headroom, power loss, kW, and a quick amp check.

Add appliances and tools to calculate the generator running and starting watt ratings needed for your planned load.

Estimate generator run time from fuel, burn rate or label runtime, reserve fuel, target hours, and optional fuel cost.

Estimate generator fuel use by fuel type, load, run time, fuel on hand, price, and editable efficiency.

Estimate inverter idle watts, Ah per day, battery runtime, kWh, cost, and savings from eco mode or a lower-idle inverter.

Estimate inverter battery runtime from Ah, voltage, load watts, efficiency, usable battery percent, duty cycle, and idle draw.