57 horsepower is 42.50489268 kW. The exact arithmetic is 57 × 0.7456998716 = 42.5048926802 kilowatts, using the defined factor rather than a rounded one, so this matches what a calibrated instrument would give you.
42.5049 kW is 57 mechanical horsepower and 57.79 metric PS. Put that through a 1,400 kg car at 80% drivetrain efficiency and the energy needed to reach 100 km/h — 540.1 kJ — takes about 15.9 seconds to deliver, which is a floor rather than a real figure because it ignores drag and traction limits.
The result sits 2.495 kW short of 45 kW, so if you need a round figure to quote, 45 kW is the honest nearest one. Plenty of people do this in their head: divide by 1.3 instead of using the exact factor 0.7456998716. At 57 that shortcut gives 43.846154 kilowatts, off by 1.341 kilowatts or about 3.16%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
The formula
57 hp- The quantity being converted
0.7456998716- Exact kilowatts in one horsepower
42.50489268 kW- The converted result
How it works, step by step
- Begin from the figure you have: 57 horsepower.
- Multiply by 0.7456998716, the exact number of kilowatts in one horsepower.
- The product is 42.5048926802 kilowatts.
- To reverse it, divide by 0.7456998716 instead: 42.50489268 kW ÷ 0.7456998716 returns 57 hp.
Worked examples
The calculation
57 hp × 0.7456998716 = 42.5048926802 kW. One multiplication, with no rounding until the value reaches the screen.
The sanity check
Divide the answer back: 42.50489268 kW ÷ 0.7456998716 returns 57 hp. If a converter fails this test it has inverted the factor, which is the single most common conversion error there is.
How to read your score
Frequently asked questions
What is 57 horsepower in kilowatts?
The answer is 42.50489268 kW — or 42.5048926802 kilowatts before any rounding.
How do you convert horsepower to kilowatts?
Use the factor 0.7456998716 as a multiplier — 57 × 0.7456998716 gives 42.50489268 kilowatts. The same factor works at any scale because the relationship is linear.
What is 42.50489268 kilowatts back in horsepower?
It goes back to 57 horsepower. The reciprocal of the factor is 1.34102209, so multiplying by that works just as well as dividing.
What does 57 hp actually look like?
42.5049 kW is 57 mechanical horsepower and 57.79 metric PS. Put that through a 1,400 kg car at 80% drivetrain efficiency and the energy needed to reach 100 km/h — 540.1 kJ — takes about 15.9 seconds to deliver, which is a floor rather than a real figure because it ignores drag and traction limits. The table lower down places it beside its neighbours so you can see where it sits.
What is a horsepower?
Mechanical horsepower, defined by James Watt as 550 foot-pounds per second.
What is a kilowatt?
The rating unit for motors, EV chargers and solar arrays.
57 hp in kilowatts — nearby values
| Horsepower | Kilowatts | Unrounded |
|---|---|---|
| 51 hp | 38.030693 | 38.03069345 |
| 52 hp | 38.776393 | 38.77639332 |
| 53 hp | 39.522093 | 39.52209319 |
| 54 hp | 40.267793 | 40.26779307 |
| 55 hp | 41.013493 | 41.01349294 |
| 56 hp | 41.759193 | 41.75919281 |
| 57 hp | 42.504893 | 42.50489268 |
| 58 hp | 43.250593 | 43.25059255 |
| 59 hp | 43.996292 | 43.99629242 |
| 60 hp | 44.741992 | 44.74199229 |
| 61 hp | 45.487692 | 45.48769217 |
| 62 hp | 46.233392 | 46.23339204 |
| 63 hp | 46.979092 | 46.97909191 |
Exact factor: 1 horsepower = 0.745699871582 kilowatts. The row for 57 hp is the value this page is about.