Torque to Tension Calculator

Inputs

Solve for

Use the same nut-factor equation in either direction.

Applied torque (T)

Tightening torque.

N·m

Nut factor (K)

≈0.20 dry, 0.15 lubricated, 0.10 anti-seize.

Nominal bolt diameter (d)

Nominal thread diameter.

Default result

Bolt tension / preload(F)

15,000N

15 kN · 3,372 lbf

Using K = 0.2.

Also computed

Required torque(T)30N·m

Method notes 2 notes

Short-form torque-tension relation: T = K · F · d. The nut factor K rolls thread and under-head friction into one empirical number.
Torque control is an estimate, not a precision preload method. Plating, lubricant, washer hardness, thread condition and reuse can move K enough to change tension dramatically.