Horsepower From Torque
Calculator
Results
- Power (SAE hp)
- 297.029702
- Power (kW)
- 221.495011
- Torque (N·m)
- 406.745384
Results
| Power (SAE hp) | 297.029702 |
| Power (kW) | 221.495011 |
| Torque (N·m) | 406.745384 |
formula-map diagram
- Power (SAE hp)
- 297.029702
- Power (kW)
- 221.495011
- Torque (N·m)
- 406.745384
Formula breakdown
Formula
hp = torque (lb·ft) × rpm ÷ 5252= 297.0297029703
Note
Simplified model: results use idealised textbook relationships and ignore real-world factors such as driving style, load, temperature, aerodynamic and rolling losses, drivetrain efficiency, tyre and brake condition and road surface. CO2 figures are tailpipe only, based on the standard 2.31 kg CO2 per litre of petrol (2.68 kg per litre of diesel), and exclude fuel production and distribution. Use them as estimates, not as legal, safety or load-rating figures.
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See all →Frequently asked questions
What is the relationship between horsepower and torque?+
Horsepower is a measure of the rate at which work is done, while torque is a measure of rotational force. They're linked through engine speed: horsepower = torque × RPM ÷ 5,252 (when torque is in lb-ft), meaning horsepower depends on both how much twisting force the engine produces and how fast it's spinning.
Why do horsepower and torque curves cross at exactly 5,252 RPM?+
This crossing point is a mathematical artifact of the constant 5,252 in the imperial horsepower formula — at that specific RPM, the numbers for horsepower and torque (in lb-ft) are always numerically equal, regardless of the engine. It's not a meaningful engineering coincidence, just how the units work out.
What's a common misconception about torque being more important than horsepower, or vice versa?+
Neither figure alone tells the full story — torque relates to how strong an engine feels off the line or under load, while horsepower (which factors in RPM) better predicts top speed and sustained power output. A high-torque, low-RPM engine and a low-torque, high-RPM engine can produce the same horsepower with very different driving characters.
How does this calculator use RPM to derive horsepower from a torque figure?+
It multiplies the entered torque value by the specified RPM, then divides by 5,252 (for lb-ft and imperial horsepower) to get horsepower at that specific engine speed. Because torque output changes across the RPM range, the result is valid only at the RPM you entered, not the engine's peak horsepower unless that happens to be the peak-torque RPM.
Why is peak horsepower usually reached at a higher RPM than peak torque?+
As RPM increases from peak torque, torque typically declines somewhat, but the RPM term in the horsepower formula grows fast enough to increase the horsepower product until the torque drop-off outweighs the RPM increase — that crossover point is where peak horsepower occurs, almost always above peak-torque RPM.