Horsepower to Torque Calculator
Convert horsepower to torque at a given RPM.
Results update as you type.
How it works
Horsepower and torque describe an engine's output in two linked ways, and this horsepower to torque calculator converts between them at any engine speed using the constant that ties them together. Enter the horsepower and the RPM at which it is produced, and it returns the torque in pound-feet, letting you recover the twisting force behind a power figure. The two measures answer different questions. Torque is the rotational force the engine applies right now, the shove you feel when you accelerate, while horsepower is the rate at which that force does work, blending torque with how fast the engine spins. Because they are related through RPM, a single horsepower number is incomplete without knowing the speed at which it occurs, which is exactly what this conversion makes explicit. The fixed constant 5252 comes from the definition of horsepower and appears wherever the two are converted. A famous consequence is that on any dyno chart the horsepower and torque curves always cross at 5252 RPM, because that is the speed at which the two values are numerically equal. Understanding the relationship helps when comparing engines, since a high-revving engine can make big horsepower from modest torque, while a low-revving diesel makes strong torque but less peak horsepower. By plugging in a power rating and the RPM it is quoted at, you can see the torque that produces it and better understand an engine's real character.
torque = horsepower × 5252 ÷ RPM
Horsepower measures the rate of doing work, which combines how much twisting force an engine makes, the torque, with how fast it spins, the RPM. Rearranging the relationship for torque means multiplying horsepower by the constant 5252 and dividing by engine speed. The number 5252 arises from the definition of one horsepower as 33,000 foot-pounds per minute divided by two pi, converting rotational speed in RPM into the units that make torque come out in pound-feet.
Source:Standard power-torque relationship (5252 constant)
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter horsepower and engine speed.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Torque updates instantly as you type — no button to press.
Frequently asked questions
Where does the number 5252 come from?
It comes from the definition of horsepower as 33,000 foot-pounds of work per minute, combined with the geometry of rotation. Converting rotational speed in revolutions per minute into the linear terms of the horsepower definition introduces a factor of two pi, and 33,000 divided by two pi equals approximately 5252. This constant links torque in pound-feet, engine speed in RPM, and horsepower into a single consistent equation used throughout automotive engineering.
Why do horsepower and torque curves cross at 5252 RPM?
Because horsepower equals torque times RPM divided by 5252, the two values are numerically equal precisely when RPM equals 5252. Below that speed torque is the larger number, and above it horsepower pulls ahead. This is not a coincidence but a direct result of the formula, which is why every dyno chart plotted in pound-feet and horsepower shows the two lines intersecting at exactly 5252 RPM, regardless of the engine.
What is the difference between torque and horsepower?
Torque is the instantaneous twisting force the engine produces, felt as the push during acceleration. Horsepower is the rate at which that force does work over time, so it accounts for how fast the engine spins as well as how hard it pushes. An engine can make the same horsepower with high torque at low RPM or low torque at high RPM, which shapes how the vehicle feels to drive.
Which matters more for driving, torque or horsepower?
Both matter, but in different ways. Torque, especially at low RPM, governs how strongly the car pulls from a stop and for towing or hauling. Horsepower, which peaks higher in the rev range, governs top speed and sustained high-speed performance. A truck prioritises low-end torque, while a sports car chases high-RPM horsepower. The best engine for you depends on whether you value effortless pulling power or high-speed capability.
Can I convert torque back to horsepower?
Yes, the relationship works both directions. To find horsepower from torque, multiply the torque in pound-feet by the RPM and divide by 5252. This is simply the same equation rearranged. Because the constant is fixed, knowing any two of the three quantities, torque, horsepower, and RPM, lets you solve for the third, which is why dyno software can display torque and horsepower curves from the same measured data.