MECHANICAL
Estimate steady shaft torque from mechanical output power and rotational speed.
Enter your values, then select Calculate.
T = (P × 1000) / (2π × RPM / 60), with T in N·m.
Use shaft output power and the speed of that same shaft. Motor electrical input requires efficiency correction. Excludes starting torque, transient loads and gearbox losses.
Calculation reviewed: 4 October 2026 · Engineering Desk Tools
Estimate steady shaft torque from mechanical output power and rotational speed. Start with measurements or documented values for the equipment and reporting period you actually want to assess. The calculator does not fill in a typical installation for you. Its blank fields help keep a demonstration value from being mistaken for your own operating data.
Choose the required options, enter the values in the labelled units and select Calculate. If a field is rejected, check its range and unit before changing it. The result is accompanied by the equation and assumptions so you can decide whether it answers your engineering question.
Record the measurement source and operating condition. Retain unrounded values for verification.
Power and speed must refer to the same shaft. A gearbox changes speed and torque, with additional losses between input and output. The relationship is a steady-state mechanical calculation; it does not describe startup, braking, impact loading or the peak torque needed to overcome friction.
T = (P × 1000) / (2π × RPM / 60), with T in N·m.
Use shaft output power and the speed of that same shaft. Motor electrical input requires efficiency correction. Excludes starting torque, transient loads and gearbox losses.
This example does not populate the form. Enter your own installation data.
| Input | Example value |
|---|---|
| Mechanical shaft power (kW) | 10 |
| Shaft speed (RPM) | 1500 |
Calculated result: 63.662 N·m. Steady shaft torque
Check the arithmetic independently using the displayed equation. Retain intermediate precision and compare the final value with your equipment documentation.
| Changed input | Calculated result |
|---|---|
| Mechanical shaft power (kW): 5 | 31.831 N·m |
| Mechanical shaft power (kW): 10 | 63.662 N·m |
| Mechanical shaft power (kW): 15 | 95.493 N·m |
These illustrative rows retain the worked example assumptions except for the varied input. They are not certified ratings or manufacturer data. Use the form for intermediate values.
Entering electrical power rather than shaft power; using motor RPM with gearbox output power; treating steady torque as a safe tightening torque. Before relying on the output, check the decimal format, unit scale and source of each value. Recheck unusual results against the formula.
No. Inputs remain blank when the tool opens or when you clear them. The worked example and table are reading material below the calculator. Enter the actual values you want to check each time, and label saved reports so their context is not lost.
The result is the steady torque the shaft carries at the entered power and speed. It does not cover starting, braking or shock loads, which can be much higher.
The allowed range follows the meaning of each input. A divisor needs a positive value; other fields may allow zero. Check the form labels and error message rather than forcing an invalid value. A rejected input must be corrected before a result can be shown.
No. Use shaft output power and the speed of that same shaft. Motor electrical input requires efficiency correction. Excludes starting torque, transient loads and gearbox losses. Use the calculation as support for a checked decision, and review equipment documentation and applicable requirements before changing an installation or operating setting.
Calculate first, then use Copy result or Print report. Some maintenance tools also provide a CSV summary. Reports contain your own entered data, so review them before sharing. You can share the public page URL without including plant records or confidential measurements.
Use the Contact page and include the tool URL, input values, units, expected output and the reference you used. Explain the measurement basis. Exclude confidential information.
Use related calculations with consistent units, periods and equipment scope.