Kilowatts to Amps Calculator

Who it's for: Electricians, service technicians, and estimators.

Use this calculator to estimate current from power, voltage, phase, and power factor assumptions.

Calculator Inputs

Next Steps

Use measured system voltage under expected operating conditions.
When power factor is unknown, start with conservative assumptions and validate.
Use the Breaker Size Calculator page for planning guidance before final code checks.

Worked Example

Example: A 5 kW single-phase load at 240 V and 0.9 power factor estimates about 23.15 A. Change phase or PF only when those assumptions match the equipment.

How This Calculator Works

The calculator converts watts to kW when needed, then uses A = (kW x 1000) / (V x PF) for single phase or A = (kW x 1000) / (sqrt(3) x V x PF) for three phase.

Converts kW to watts and applies phase-specific current formulas.
Uses single-phase or three-phase denominator terms based on selected phase.
Applies user-selected power factor to produce an estimated current value.

Phase Formula Reference

Item	Value	Use
Single phase	A = kW x 1000 / (V x PF)	Uses voltage and power factor.
Three phase	A = kW x 1000 / (sqrt(3) x V x PF)	Adds the three-phase sqrt(3) factor.
PF range	0.1 to 1.0	Input must match known equipment assumptions.

Common Mistakes

Applying a single-phase formula to a three-phase load.
Leaving power factor at the default when equipment data says otherwise.
Using load current alone as final circuit sizing.

FAQ

Yes. Three-phase current uses a different equation than single-phase and can significantly change estimated amperage.

Use equipment data when available; if unknown, use a planning assumption and verify with measured or manufacturer values.

No. Treat this as a starting estimate and complete final sizing with code tables, equipment nameplates, and engineering judgment.

When to Call a Professional

Use a licensed electrician or engineer when the Kilowatts to Amps Calculator result affects final circuit sizing, equipment protection, or code compliance.

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Conclusion

Use the Kilowatts to Amps Calculator result to understand estimated amps, equation used, phase and pf notes from kilowatts (kw), voltage (v), phase (single/three). Keep the input assumptions with the result so another person can reproduce the same estimate.

About This Calculator

About this calculator: Electricians, service technicians, and estimators.

Educational planning estimate. Verify final electrical work against applicable code, equipment data, and qualified professional judgment.

Written by BuildCalcTools Team - Kilowatts to Amps Calculator methodology and field-use notes.

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