Amps to Kilowatts Calculator

How it works

DC or single-phase kilowatts = amps × volts × power factor ÷ 1,000. Balanced three-phase kilowatts = √3 × line current × line-to-line volts × power factor ÷ 1,000.

Worked example: 20 A at 230 V and 0.8 power factor

Multiply 20 A × 230 V × 0.8, then divide by 1,000. The result is 3.68 kW of real power.

At power factor 1, the same voltage and current would equal 4.6 kW. Power factor therefore changes the real kilowatts even when the volt and amp readings stay the same.

Amps alone cannot determine kilowatts

Current must be paired with voltage. Ten amps at 12 V DC is 0.12 kW, while 10 A at 230 V single-phase is 2.3 kW at power factor 1. For AC, real power also depends on power factor and the selected system.

For a balanced three-phase load at 400 V line-to-line and power factor 0.8, 10 A is about 5.54 kW. Unbalanced systems need phase-by-phase measurements rather than this balanced-load shortcut.

Kilowatts are power, not energy or electricity cost

The result describes a rate at one operating condition. To estimate energy, multiply kW by hours: a 3.68 kW load held for 2 hours uses 7.36 kWh. Multiply that energy by your electricity rate to estimate cost.

Motors, compressors, chargers, and variable-speed equipment may not hold one current or power factor throughout a cycle. Use representative measured values when estimating energy, and use nameplate/manufacturer requirements for electrical sizing.

Sources used for assumptions: Schneider Electric — single-phase and balanced three-phase power calculations; U.S. Energy Information Administration — electricity glossary; Klein Tools — CL390 true-RMS clamp meter specifications.

Frequently asked questions