Validate friction
Use test data or qualified supplier documentation, not an undifferentiated table value.
Bolted joints
Bolt Tightening Torque Calculator
Determine tightening torque from target preload using separate thread and bearing friction coefficients.
ISO898
02
Results
Set the inputs and start the calculation.
Torque is only the control variable
What this calculator does
Target preload, thread size, bearing diameter, and separate friction coefficients determine required tightening torque.
Friction consumes most tightening torque. A calculated nominal value is meaningful only when surface, lubrication, and bearing geometry are controlled.
Typical tasks
- Prepare an assembly window
- Compare lubrication states
- Translate target preload into nominal torque
Design notes and follow-up standards
Check before release
Account for scatter
One nominal torque does not represent tool and friction variation.
Verify the joint
Clamp load, embedding loss, service load, and fatigue belong in a complete joint assessment.
Useful follow-up standards
ISO 16047
Testing torque/preload behaviour and separated friction coefficients.
VDI 2230 Part 1
Systematic design of highly stressed single-bolt joints.
ISO 6789
Requirements and calibration for hand torque tools.