AIEngineeringTool

Bolt Preload Calculator

Estimate proof load and target preload for a bolted joint.

Tensile stress area: 84.3 mm²
Live concept view — geometry scales with the entered design condition.

Estimate proof load and target preload for a bolted joint.

Design inputs

Enter known values using the units shown. Results and the live SVG view update immediately.

PRELIMINARY RESULT

Proof load50,580 N

Target preload: 35,406 N

Proof load
50,580 N
Target preload
35,406 N

Calculation detail

Formula: Fproof = As × Sp; Fpreload = Fproof × target percentage

Proof load and target preload are estimated from tensile stress area and specified proof strength.

FORMULA VERIFICATION

Units, scope and reference

Reference: VDI 2230 and Shigley bolted-joint principles.

Internal unit basis: N/mm² × mm². Outputs: N.

Valid conditions: Positive area and proof strength; preload target from 0–100%.

Limitations: No torque coefficient, friction, joint stiffness or tightening-method model.