Unit tools
Units: hp, kW, PSHP to kW converter for tractors
This converter converts engine power between mechanical horsepower (hp), kilowatts (kW), and metric horsepower (PS). Use it to compare US and European tractor ratings in the same unit.
Quick reference
Common tractor sizes in hp, kW, and PS
Estimated PTO hp is 86 percent of engine hp (see the PTO horsepower calculator). Each row links to tractors in that horsepower class.
| Engine hp | kW | PS | Est. PTO hp | Class |
|---|---|---|---|---|
| 20 | 14.9 | 20.3 | 17 | Under 25 HP tractors |
| 25 | 18.6 | 25.3 | 22 | 25–40 HP tractors |
| 35 | 26.1 | 35.5 | 30 | 25–40 HP tractors |
| 45 | 33.6 | 45.6 | 39 | 40–60 HP tractors |
| 60 | 44.7 | 60.8 | 52 | 60–100 HP tractors |
| 75 | 55.9 | 76.0 | 65 | 60–100 HP tractors |
| 100 | 74.6 | 101.4 | 86 | 100–150 HP tractors |
| 125 | 93.2 | 126.7 | 108 | 100–150 HP tractors |
| 150 | 111.9 | 152.1 | 129 | 150–300 HP tractors |
| 200 | 149.1 | 202.8 | 172 | 150–300 HP tractors |
| 250 | 186.4 | 253.5 | 215 | 150–300 HP tractors |
| 300 | 223.7 | 304.2 | 258 | 300+ HP tractors |
| 400 | 298.3 | 405.5 | 344 | 300+ HP tractors |
| 500 | 372.9 | 506.9 | 430 | 300+ HP tractors |
| 600 | 447.4 | 608.3 | 516 | 300+ HP tractors |
Method
Conversion factors
1 mechanical horsepower (hp) = 745.7 watts = 0.7457 kW. 1 metric horsepower (PS) = 735.5 watts = 0.7355 kW. So 1 PS = 0.9863 hp, and 1 kW = 1.341 hp = 1.360 PS.
Tractor spec pages on this site show engine power in both hp and kW. When a European brochure quotes PS, convert to hp before comparing it with a US rating.
FAQ
Frequently asked questions
How do I convert hp to kW?
Multiply horsepower by 0.7457. A 100 hp tractor is 74.6 kW. To go from kW back to hp, divide by 0.7457 (or multiply by 1.341).
What is the difference between hp and PS?
hp here means mechanical (imperial) horsepower, 745.7 watts, used on US spec sheets. PS (also written CV or ch) is metric horsepower, 735.5 watts, common on European tractor brochures. A tractor rated 100 PS is about 98.6 hp, so PS figures look about 1.4 percent larger for the same engine.
Why do kW and hp ratings for the same tractor not match exactly?
Brochures often quote power to different standards (SAE J1995 gross, SAE J1349 net, ISO 14396, ECE R120, 97/68/EC) and sometimes include boost or power management. Convert the units first, then check that both figures use the same rating standard before comparing tractors.
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Rated horsepower, operating weight, and tire sizes for each model are listed in the tractor spec database. Models can also be browsed by manufacturer.