# Torque to Horsepower Calculator

URL: https://speedycalculator.com/calculators/conversion/torque-to-horsepower/
Last updated: 2026-10-25

> The torque to horsepower calculator converts engine torque and speed into power in horsepower and kilowatts, using the relation P = T × ω.

## Inputs

- Torque (lbf·ft, N·m, kgf·m)
- Engine speed (rpm)

## Results

- Power
- In kilowatts

## Formula

```
hp = torque (lb·ft) × rpm ÷ 5,252
P (W) = T (N·m) × 2π × rpm ÷ 60
```

## Explanation

Horsepower and torque are linked by engine speed: power is torque times rotational speed. That is why horsepower and torque curves (in lb·ft) always cross at 5,252 rpm.

### How to use the Torque to Horsepower Calculator

- **Torque**
- **Engine speed**
- Every result field is editable: type into **Power** or any other result and **Engine speed** plus every other field update to match.

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Torque is converted to newton-metres, rpm to radians per second, and the two are multiplied to give watts.

### Inputs explained

FieldWhat to enterTorqueUnits: lbf·ft, N·m, kgf·mEngine speedIn rpm

### What each result means

- **Power** = [Torque] × 2 × pi × [Engine speed] ÷ 60
- **In kilowatts** = [Torque] × 2 × pi × [Engine speed] ÷ 60

### Example values

How the main result changes when **Engine speed** changes and everything else stays at the example values above:

Engine speed (rpm)Power (hp)2,6261503,9392255,252299.996,565374.997,878449.9910,504599.99

## Worked example

Inputs — Torque: 300 lbf·ft; Engine speed: 5,252 rpm.

Results — **Power = 299.99 hp**; In kilowatts = 223.71 kW.

## FAQ

**Why do torque and hp curves cross at 5,252 rpm?**
Because hp = lb·ft × rpm ÷ 5,252, they are equal at that speed.

**How much hp is 400 N·m at 6,000 rpm?**
About 337 hp (251 kW).

**What formula does the Torque to Horsepower Calculator use?**
hp = torque (lb·ft) × rpm ÷ 5,252.


## Sources

- [NIST Special Publication 811 – Guide for the Use of the International System of Units](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44 Appendix C – General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)