What is torque?
Torque is a rotational force—force applied at a distance from an axis.
Torque Calculator
Compute torque from a force at a radius, or from shaft power and rotational speed.
Calculate torque
Choose force×distance or power/RPM mode, then enter the inputs.
About this calculator
How to use Torque Calculator, plus the formulas and logic behind the results.
Tool description
The Torque Calculator estimates twisting moment from force and lever arm, or from transmitted power and RPM. Results are shown in N·m and lb·ft.
How to use
- Select force×distance or power/RPM.
- Enter force & distance, or power & RPM (and choose kW or HP).
- Select Calculate to view torque in N·m and lb·ft.
Formulas & reference
τ = F × rτ_Nm = 9550 × P_kW ÷ n_rpmτ_lbft = 5252 × HP ÷ n_rpmτ_lbft = τ_Nm × 0.737562
Torque formulas
- τ (N·m) = F (N) × r (m)
- τ (N·m) ≈ 9550 × P(kW) ÷ RPM
- τ (lb·ft) ≈ 5252 × HP ÷ RPM
- 1 N·m ≈ 0.73756 lb·ft
Calculation logic
Force×distance multiplies SI force and radius. Power/RPM uses standard mechanical identities for kW or HP, then converts units for display.
Power/RPM torque assumes steady rotational power at the shaft. Friction and efficiency losses are not included unless you adjust power first.
Torque Calculator FAQ
Common questions about this calculator and how to use the results.
How do I convert N·m to lb·ft?
Multiply N·m by about 0.73756.
Which power unit should I choose?
Use kW for metric shaft power or HP for mechanical horsepower.
Does RPM of zero work?
No. RPM must be greater than zero in power/RPM mode.
Is motor efficiency included?
No. Enter shaft power after losses, or derate input power yourself.
Can distance be in centimeters?
Convert to meters first (cm ÷ 100).