Bolt Torque to Tension Calculator
Clamp force a given torque produces — the K-factor (nut factor) equation.
90% of your torque fights friction; only ~10% stretches the bolt. Changing lubrication changes clamp force ±40% at the SAME torque — K is the whole game.
Formula
Bolt Torque to Tension Calculator is a free torque to tension for design engineers, metallurgists and QA inspectors — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Bolt Torque to Tension Calculator
Clamp force a given torque produces — the K-factor (nut factor) equation. The calculation implements T = K·F·d → F = T/(K·d) (VDI 2230; Bickford, Introduction to the Design of Bolted Joints). 90% of your torque fights friction; only ~10% stretches the bolt. Changing lubrication changes clamp force ±40% at the SAME torque — K is the whole game.
How to use Bolt Torque to Tension Calculator
- 1Enter Applied torque in N·m.
- 2Enter Bolt nominal diameter in mm.
- 3Enter Nut factor K (Dry steel 0.2 · lightly oiled 0.15 · moly paste 0.10 · zinc 0.22).
- 4Read Bolt tension (preload) instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Bolt Torque to Tension Calculator?
- ✓Implements the standard formula — T = K·F·d → F = T/(K·d)
- ✓Reference cited on-page: VDI 2230; Bickford, Introduction to the Design of Bolted Joints
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Bolt Torque to Tension Calculator use?+
It computes T = K·F·d → F = T/(K·d), per VDI 2230; Bickford, Introduction to the Design of Bolted Joints. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
90% of your torque fights friction; only ~10% stretches the bolt. Changing lubrication changes clamp force ±40% at the SAME torque — K is the whole game.
Where do the material property defaults come from?+
Defaults are standard handbook values (ASM, manufacturer datasheets, the cited standard). Always substitute certified values from your material's test certificate for critical work.
Is the Bolt Torque to Tension Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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