إن Bolt Preload Calculator is a practical engineering tool designed to estimate the required preload force and tightening torque for bolted connections. By considering bolt diameter, thread pitch, material strength, preload percentage, and friction conditions, it helps engineers determine suitable bolt tension and clamping force for reliable assemblies. The Bolt Preload Calculator supports mechanical design, installation, and maintenance while helping reduce the risks of bolt loosening, insufficient clamping, excessive stress, fatigue damage, and premature joint failure.

Bolt Preload Calculator | Bolt Tightening Torque & Clamp Force

Input parameters

1 Bolt geometry
Metric: At = π/4 × (d − 0.9382 p)². UN: At = π/4 × (d − 0.9743/n)². ISO 898-1 M12 coarse is 84.3 mm².
2 Material strength
3 Target preload
4 Friction & tightening

When both friction coefficients are provided, tightening torque uses T = Fأنا [p / 2π + 0.577 μt د2 + 0.5 μb دم]. Otherwise the simplified relation T = K Fأنا d is used.

5 Joint load (optional)