Torque and Horsepower Calculator
Leave any one of the three blank and it will be solved from the other two.
| Horsepower | 571.2 | hp |
| Torque | 500.0 | lb-ft |
| RPM | 6,000 | rpm |
| Power | 425.9 | kW |
| Torque | 677.9 | N·m |
- horsepower = torque (lb-ft) × RPM ÷ 5252
- 5252 = 33,000 ft·lb per minute ÷ 2π
- 1 hp = 0.7457 kW · 1 lb-ft = 1.3558 N·m
When you need it
When converting dyno figures, comparing engines, or checking whether a claimed number is internally consistent.
The 5252 crossover
Torque and horsepower always cross at 5,252 RPM, because that is where RPM divided by 5,252 equals one. It is arithmetic, not a property of any particular engine.
It is also a quick lie detector. If a published dyno graph shows the two curves crossing anywhere other than 5,252, either the axes are scaled differently or the graph has been redrawn by someone who did not understand it.
Which number to care about
Torque multiplied by gearing is what accelerates the car; horsepower is the rate at which that work gets done, and it is what determines how much gearing you can afford to use. Neither is the whole story on its own.
A broad, flat torque curve feels stronger on the road than a peaky one with a bigger headline figure, because you spend your time under the curve rather than at its peak. Area under the curve across the RPM you actually use beats peak numbers.
Compare like with like
Chassis dyno figures run roughly twelve to twenty percent below crank figures depending on the drivetrain, and different correction standards differ by around four percent between them. Comparing an SAE-corrected chassis number with an uncorrected engine dyno number tells you nothing.