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Conversion • Amps • kW

Convert Amps to kW

Convert current in amps to electrical power in kW.

Calculation Values

Note: This calculator provides a technical estimate for guidance only. For electrical installations, standards, protective measures, installation method, ambient temperature, grouping, protective devices and manufacturer specifications must also be checked.

Formula Used

Single-phase: P = U × I × cos φ

Three-phase: P = √3 × U × I × cos φ

The result is calculated in watts and then displayed in kilowatts.

Frequently Asked Questions

Why does the same current yield more power on three-phase?

On three-phase systems, power is transmitted across three phases. That's why the formula includes the factor √3.

Can I ignore cos φ?

For purely resistive loads, cos φ is approximately 1. For inductive loads, the power factor should be taken into account.

What is kW?

Kilowatt is a unit of power. 1 kW equals 1000 watts.

Practical guidance

Derive electrical active power from amperes

Current alone does not define power; voltage, electrical system and power factor are also required.

Input values explained

Current
Enter the expected operating current, not a fuse rating. Motors and electronic power supplies may draw much higher starting or peak currents.
Voltage
Match the voltage to the selected electrical system. Single-phase calculations use line-to-neutral voltage, while three-phase calculations use voltage between two line conductors.
Power factor cos φ
cos φ is the ratio of active to apparent power. It is close to 1 for resistive heating loads; use the data-sheet value for motors and transformers.
Electrical system
Choose single-phase AC for a 230 V circuit and three-phase for a balanced three-phase system. This selection changes the formula factor.

Example: 16 A three-phase

At 400 V, 16 A and cos φ 0.90, calculate balanced active power.

P = √3 × 400 V × 16 A × 0.90 ≈ 9.98 kW

Electrical active power is about 9.98 kW. Mechanical motor output may be lower because of efficiency losses.

Use a representative measured current

Use stable operating current. A peak or one unbalanced phase can give a misleading total-power result.

Calculation limits

  • Harmonics and nonsinusoidal current are not assessed.
  • Unbalanced systems require proper three-phase power measurement.