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Bolt Torque Calculator

Estimate tightening torque from clamp force, bolt diameter, and a nut factor K.

 

 

 

Torque (N·m)

About this calculator

Use this calculator for T = K × F × d. Enter the clamp force in kN, the nominal diameter, and K (often 0.2 for as-received steel).

Torque (N·m) = K × (force in N) × (diameter in m). Diameter can be entered in millimetres (mm) or inches (in). Force stays in kN; K is dimensionless.

This is a nut-factor estimate. It is not a tensioned-bolt stretch or a lubricant-specific table.

Force (kN): Target clamp force in kilonewtons.

Diameter: Nominal bolt diameter, in mm or in.

K: Nut factor. Dry steel is often around 0.2; lubricated is lower.

Torque (N·m): Estimated tightening torque.