HP to kW Converter: Horsepower, Kilowatts and Torque

HP to kW: 1 hp = 0.745 699 872 kW, so kW = hp × 0.7457 and hp = kW × 1.341. A 300 hp engine makes 223.7 kW. European brochures often quote metric horsepower (PS), which is about 1.4 % smaller – this converter handles both.

Example: What do you know: Power in hp, kW or PS · Power 300 · Unit: hp (mechanical, 550 ft·lbf/s) · Displacement (optional) 0 cc → Result: 300 hp = 223.7 kW = 304.2 PS. Source: NIST SP 811 App. B.9, NIST SP 811 – Guide for the Use of the SI, Appendix B.9: horsepower (550 ft·lbf/s), horsepower (metric), horsepower (electric), pound-force foot. Updated: 30 September 2026.

What do you know?

Power

Unit

Displacement (optional)

for power per litre, 0 = skip

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Result

Result: 300 hp = 223.7 kW = 304.2 PS
In all units: Unit Value
Kilowatts 223.71 kW
Metric horsepower (PS) 304.16 PS
Mechanical horsepower (hp) 300 hp
Electric horsepower 299.88 hp (el.)
Watts 223,710 W
Step by step: In watts: 300 hp × 745.7 W = 223,710 W
In kW: 223,710 W / 1,000 W = 223.71 kW
In PS: 223,710 W / 735.5 W = 304.16 PS; Note: mechanical hp (745.7 W) is about 1.4 % larger than metric horsepower, PS (735.5 W). European PS figures are therefore slightly lower when expressed in hp.

Unit	Value
Kilowatts	223.71 kW
Metric horsepower (PS)	304.16 PS
Mechanical horsepower (hp)	300 hp
Electric horsepower	299.88 hp (el.)
Watts	223,710 W

How it is calculated

Formula: hp to kW and kW to hp

Mechanical horsepower (hp) is defined as 550 foot-pounds-force per second. With the exact foot, pound and standard gravity this is 1 hp = 745.699 872 W (NIST SP 811: 7.456 999 E+02 W). So:

kW = hp × 0.745 7
hp = kW × 1.341 02

Table: common values

hp	kW	kW	hp
100 hp	74.6 kW	50 kW	67.1 hp
150 hp	111.9 kW	100 kW	134.1 hp
200 hp	149.1 kW	150 kW	201.2 hp
300 hp	223.7 kW	200 kW	268.2 hp
500 hp	372.8 kW	300 kW	402.3 hp

hp, PS, bhp and electric hp

Metric horsepower (PS, CV, ch, pk) is 75 kilogram-force metres per second = 735.498 75 W, used in continental Europe and Japan. Electric horsepower is exactly 746 W and appears on motor nameplates. bhp (brake horsepower) is mechanical hp measured at the crankshaft. All factors come from NIST SP 811, Appendix B.9.

Power from torque and rpm

Power is torque times angular speed: P = T · 2π · n / 60 (T in N·m, n in rpm, P in W). In US units the shortcut is hp = lb·ft × rpm / 5252 – which is why torque and horsepower curves cross at 5,252 rpm. Example: 320 N·m at 4,000 rpm gives 134 kW or 180 hp. Use torque and rpm from the same point on the curve.

Specific output

Dividing power by displacement shows how hard an engine is tuned: a 2.0-litre engine with 110 kW delivers 55 kW per litre (73.8 hp/L).

Frequently asked questions

How do you convert hp to kW?

Multiply by 0.7457. Example: 300 hp × 0.7457 = 223.7 kW.

How do you convert kW to hp?

Multiply by 1.341. Example: 100 kW × 1.341 = 134.1 hp. For metric horsepower (PS) multiply by 1.36 instead.

Is PS the same as hp?

No. PS (metric horsepower) is 735.5 W, hp is 745.7 W. 300 PS is about 296 hp, so European figures look slightly higher in PS than in hp.

How do you calculate horsepower from torque?

hp = torque (lb·ft) × rpm / 5252. In metric units: kW = torque (N·m) × rpm / 9549. Example: 300 lb·ft at 5,000 rpm = 285.6 hp.

What is 1 hp in watts?

Mechanical hp is 745.7 W (exactly 745.699 872… W), electric hp is 746 W and metric hp is 735.5 W.

Sources and legal basis

As of: 30 September 2026