Convert torque in Nm and rotational speed in RPM to kW, or solve for torque or RPM, with lb-ft, hp, PS, watts, and rad/s support.

Use torque, speed and mechanical power at the same shaft and operating point. Inputs are nonnegative magnitudes. This does not estimate electrical input power, efficiency, drivetrain losses or equipment limits.

Nm to kW Formula

Use torque and rotational speed at the same shaft and operating point to calculate mechanical shaft power. Torque alone does not determine power. P = Tω does not require an efficiency factor; electrical input power or power at a different shaft needs separate efficiency or loss information.

P = (T × 2 π × RPM) / (60 × 1000) (kW)

Variables:

  • P is power in kilowatts (kW)
  • T is torque in newton-meters (Nm)
  • RPM is rotational speed in revolutions per minute

Tip: A handy shortcut is kW ≈ T × RPM / 9550 (because 9550 ≈ 60×1000 / 2π).

Newton-meters to kilowatts (at 1500 RPM)
Torque (Nm) Power (kW)
50.785
101.571
152.356
203.142
304.712
406.283
507.854
7511.781
10015.708
12519.635
15023.562
20031.416
25039.270
30047.124
* Rounded to 3 decimals using kW = N·m × RPM × 2π / 60000. Assumed RPM: 1500. The 9550 denominator is only a rounded shortcut. At 1500 RPM: 1 N·m ≈ 0.157080 kW.

How to Calculate kW from Nm

  1. Note the torque T in newton-meters and the speed RPM.
  2. Apply kW = (T × 2π × RPM) / (60 × 1000) or the shortcut kW ≈ T × RPM / 9550.
  3. Compute power in kilowatts and verify with the calculator above.

Example: With T = 120 Nm at 1500 RPM, power ≈ 120 × 1500 / 9550 = 18.85 kW.