Formula and calculation method
Watts = torque × 2π × rpm / 60. Mechanical hp = watts / 745.6998716.
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
How to use horsepower calculator
- Set Torque (N·m). The example below uses 250.
- Set Speed (rpm). The example below uses 4000.
- Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.
Worked example
Example inputs
- Torque (N·m)
- 250
- Speed (rpm)
- 4000
- Power (kW)
- 104.71975512
- Mechanical horsepower
- 140.43150483
Inputs and results explained
Horsepower Calculator takes 2 inputs. Fill each one using the same units and conventions, then select Calculate.
- Torque (N·m): a number of 0 or more. The worked example uses 250.
- Speed (rpm): a number of 0 or more. The worked example uses 4000.
The result panel reports Power (kW) and Mechanical horsepower, so you can see the whole outcome rather than a single figure.
Factors affecting your result
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Changing torque (n·m) changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.
Frequently asked questions
How does the horsepower calculator work?
Watts = torque × 2π × rpm / 60. Mechanical hp = watts / 745.6998716.
What inputs does Horsepower Calculator need?
Enter torque (n·m), speed (rpm). Choose values that correspond to the same situation and measurement convention.
How should I interpret the horsepower calculator result?
Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.
Are my horsepower calculator inputs uploaded?
No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.
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