🔧 Fastener Torque Calculator

Calculate proper bolt tightening torque for metric and imperial fasteners. Supports all common grades, coatings, and lubrication conditions. Based on ISO 898-1 / SAE J429 / ASME B1.1.

Bolt Size

Grade / Class

Lubrication / Coating

Preload (% of Proof Load)

Calculated Tightening Torque

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N·m (Newton-meter)

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ft·lb

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in·lb

—

kg·m

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Clamping Force (kN)

💡 Torque-angle method: For critical joints (engine, structural), torque to 30% of target, then add the specified angle. Always follow OEM specifications when available.

Quick Reference: Common Torque Values

Metric Coarse, Class 8.8, dry assembly (K=0.20)

Size	Stress Area (mm²)	Proof Load (kN)	Torque (N·m)	Torque (ft·lb)

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