Bolted Joint Torque Calculator_

Calculate proper tightening torque for bolted joints based on material and preload requirements

Quick Select

Nominal Diameter (mm)

Thread Pitch (mm)

Tensile Strength (MPa)

Grade 8.8 = 400 MPa, Grade 10.9 = 640 MPa

Friction Coefficient (K)

Dry steel = 0.2, Lubricated = 0.15

Safety Factor

Target Preload (% of max)

Typical: 60-80%

0.0

N·m

0.00 kN

0 N

0.0 MPa

0.0% of tensile strength

0.0 mm²

Tensile stress area (approximation)

• Formula: T = K × D × F (Torque = Coefficient × Diameter × Preload Force)
• K factor varies with lubrication (dry ≈ 0.20, lubricated ≈ 0.15, anti-seize ≈ 0.10)
• Typical preload: 60-80% of proof strength for reusable joints
• Use torque wrench for accurate tightening
• Always follow manufacturer specifications when available
• This calculator provides estimates - verify for critical applications