Horsepower Calculator
HP = torque × RPM ÷ 5,252 — or watts ÷ 745.7. Click any i for detail.
Power
Method
i
Method
Crank-style HP from a torque/RPM pair, or a watts conversion. |
|
|---|---|
Torque (lb-ft)
i
Torque
Brake torque at that RPM. |
|
RPM
i
RPM
Engine speed for that torque number. |
|
Watts
i
Watts
Electrical or mechanical watts to convert. |
How to use this calculator
- Pick torque×RPM or watts.
- Enter the matching fields.
- Read HP.
- Displacement and gear ratio are separate.
Results explained
Imperial: HP = T × RPM / 5252. Watts: HP = W / 745.7. Metric PS (~735.5 W) is not used.
Quick reference: horsepower
350 lb-ft at 4,000 RPM is about 266 HP.
| Item | Detail |
|---|---|
| Constant | 5,252 |
| 1 HP | ≈ 745.7 W |
| Wheel vs crank | Not modeled |
| Three-phase kW | Three-phase power calculator |
A chassis dyno measures a different station in the driveline.
How the estimate is built
HP = T×RPM/5252, or W/745.7.
Example scenario
350 lb-ft × 4,000 / 5,252 → 266 HP.
FAQ
N·m torque?
Convert to lb-ft (÷ 1.3558) first.
Electric motors?
Use watts mode from the nameplate.
SAE vs DIN?
This is the 5,252 identity, not a test standard.