HP to kW Calculator

Convert HP to kW (or reverse kW / W to horsepower) instantly—bidirectional unit conversion for motors and engines with mechanical, electrical, and metric HP.

Calculator

Quick: HP → kW (mechanical). Advanced: reverse direction, switch W/kW, and pick HP type.

Conversion direction

Horsepower type Match the nameplate definition. Default is US mechanical (imperial) HP.

Horsepower (HP) Example: 1 hp motor nameplate or 10 hp pump. Shaft output unless stated otherwise.

About this calculator

This HP to kW calculator converts mechanical, electrical, and metric horsepower ↔ W/kW. It is not a Motor FLA sizer—use the Motor FLA calculator for line current from HP, voltage, efficiency, and PF. Browse the power calculator hub.

Calculation Results

≈ 0.7457 kW (745.7 W)

1 hp (Mechanical HP) → 0.7457 kW · 745.7 W

Formula: kW = hp × 0.745699872

Nameplate HP is usually shaft output, not electrical input. Electrical input is higher when efficiency < 100%. Boiler HP is not supported.

Continue Your Calculation

Have shaft HP? Continue to Motor FLA for line current from HP, voltage, efficiency, and PF.

Motor FLA →

HP to kW quick reference

Mechanical (imperial) HP = 745.699872 W. Click a row to load the calculator.

Input	Context	Result
	Small motor / engine	≈ 0.7457 kW
	Pump / compressor class	≈ 3.7285 kW
	Industrial motor	≈ 7.4570 kW
	Tool / appliance rating	≈ 2.011 hp
	IEC ≈ 10 hp class	≈ 10.059 hp

HP to kW formula

Mechanical HP → kW: kW = hp × 0.745699872

Electrical HP → kW: kW = hp × 0.746

Metric HP (PS) → kW: kW = hp × 0.73549875

kW → HP (mechanical): hp = kW ÷ 0.745699872 ≈ kW × 1.34102209

Mechanical HP — 745.699872 W (US motors/engines, default)
Electrical HP — exactly 746 W (NEMA definition)
Metric HP (PS/CV) — 735.49875 W (EU nameplates)

Example: 1 × 0.745699872 ≈ 0.7457 kW (745.7 W).

Need line current from shaft HP? Motor FLA calculator. Need amps from watts? Watts to Amps.

When to use which tool

Goal	Tool
Convert HP ↔ W/kW (unit conversion)	This page
Motor FLA from HP/kW + V/eff/PF	Motor FLA
Convert watts ↔ amps	Watts to Amps
Convert amps ↔ kW	Amps to kW
Convert W/kW ↔ BTU/h	Watts to BTU

Frequently Asked Questions

How do I convert HP to kW?

Multiply mechanical horsepower by 0.745699872. Example: 1 hp(mech) ≈ 0.7457 kW (745.7 W). Electrical HP uses 0.746 kW per hp; metric HP (PS) uses 0.73549875 kW per hp.

How do I convert kW or watts to horsepower?

Divide watts by the HP factor (745.699872 / 746 / 735.49875), or divide kW by the same factor ÷ 1000. Example: 7.5 kW ≈ 10.06 mechanical hp.

What is the difference between mechanical, electrical, and metric HP?

Mechanical = 745.699872 W (US motors/engines). Electrical = 746 W (NEMA). Metric (PS/CV) = 735.49875 W (EU nameplates). Always match the label definition.

Is nameplate HP the same as electrical input power?

Usually no. Nameplate HP is typically shaft output. Electrical input is higher because of efficiency. Use Motor FLA with V, eff, and PF for line current.

Does this calculator support boiler horsepower?

No. Boiler HP (≈9.81 kW) is a steam rating. This page converts mechanical, electrical, and metric motor/engine HP only.