My air compressor says 1.5 hp but the motor nameplate shows watts. How do I verify the rating?

Multiply hp by 745.7 to get watts. A true 1.5 hp motor should draw about 1,119 W at full load. Many budget compressors overstate hp, so checking the watt rating on the nameplate is more reliable.

The electric motor I need is listed as 2,200 W — what hp is that for sizing a belt drive?

2,200 W ÷ 745.7 ≈ 2.95 hp. Round up to a 3 hp belt and pulley system to avoid running at the edge of capacity.

My EV has a 150 kW motor. How does that compare to a gasoline car's horsepower?

150 kW = 150,000 W ÷ 745.7 ≈ 201 hp. That's comparable to a mid-range performance sedan. Unlike combustion engines, electric motors deliver this torque instantly from zero RPM.

Is a watt-to-horsepower conversion different for electric vs. mechanical horsepower?

Mechanical horsepower (used for engines and motors) is exactly 745.69987 W. Electrical horsepower is defined as exactly 746 W — a 0.04% difference that's negligible for most practical purposes.

Watts to Horsepower Converter

Enter a value to instantly convert between power units.

From

Precision4 dp

1 Watt = 0.0013 Horsepower (mech)

Key Formulas

Kilowatt → Horsepower (mech)

hp = kW × 1.34102

Horsepower (mech) → Kilowatt

kW = hp × 0.7457

Watt → Kilowatt

kW = W × 0.001

Kilowatt → Watt

W = kW × 1000

Formula

hp = W ÷ 745.69987

When shopping for an electric motor, pump, or generator, specs often appear in watts while the mechanical requirement is listed in horsepower. Electric vehicles quote motor output in kW or watts; traditional engine comparisons use hp. Knowing 746 W ≈ 1 hp lets you judge whether a 1500 W shop vacuum has enough suction power, or whether a 3,700 W submersible pump matches the hp rating on a well system.

Source: NIST SP 811, Table B.8

Last reviewed: 2026-06-11 · see our methodology

Frequently Asked Questions

Real-World Examples

A 746 W electric motor delivers exactly 1 mechanical horsepower — the standard reference point for motor sizing charts.

746 W = 1 hp

A 1500 W workshop table saw produces about 2 hp, matching the minimum recommended for hardwood ripping.

1500 W = 2.01 hp

A 3700 W submersible well pump is rated at roughly 5 hp, aligning with standard residential well-pump categories.

3700 W = 4.96 hp

An 11,190 W electric motor on a commercial HVAC compressor equals 15 hp — a common industrial motor frame size.

11190 W = 15 hp

kw to hp hp to kw watts to kw kw to watts mw to kw kw to mw

Watts to Horsepower Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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