Horsepower Calculator
Calculate horsepower from torque and RPM — HP = (torque × RPM) / 5252.
How to Use
- Enter torque (lb-ft) and RPM — horsepower is computed instantly, with kW and Nm alongside.
- The chart shows how HP rises with RPM and crosses the torque line at 5252.
- For a full dyno-style curve across the whole rev range, use the HP & Torque Lab.
| 1 hp | 0.7457 kW |
| 1 kW | 1.341 hp |
| 1 hp | 1.014 PS (metric hp) |
| 1 lb-ft | 1.3558 Nm |
| 1 Nm | 0.7376 lb-ft |
Show Work
Formulas
About the Horsepower Calculator
Whether you are at a desk or on your phone, the Horsepower Calculator makes automotive and vehicle projects easy — and it is completely free. Calculate horsepower from torque and RPM — HP = (torque × RPM) / 5252.
How it works
Type your numbers into the boxes. The answer shows up right away — you do not have to press a button. If you change a number, the answer changes too. So you can try different numbers and watch what happens, or check an answer you worked out yourself. Just make sure each box has the right kind of number in it.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
Where does 5252 come from?
The conversion constant for lb-ft and RPM to horsepower: 33 000 ft-lb/min per hp ÷ 2π rad/rev.
Why does HP always equal torque at 5252 RPM?
It's the crossover point of the formula — at 5252 RPM the torque number in lb-ft equals the HP number.
How do I use the Horsepower Calculator?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Is it free? Does it work without internet?
Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.
Where does my data go?
Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.
Common Use Cases
Dyno sanity check
Verify shop dyno numbers.
Engine shopping
Compare torque curves to peak HP.
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