Calculates bolt torque specifications for various SAE and metric sizes and grades. Provides results in both ft-lb and N·m, accounting for dry or lubricated conditions. Works offline without ads or subscriptions.
1.0.6
October 28, 2026
Optimized for iPhone Duo and iPad: on wide screens, inputs and results now sit side by side so you can see the answer change as you type. Built with the iOS 27 SDK.
MoreBolt Torque Spec Calc covers SAE grades 2, 5, and 8 across 28 sizes from #6-32 to 1-1/2 inch, and Metric classes 4.6, 8.8, 10.9, and 12.9 across 17 sizes from M3 to M36.
It uses the formula T = K x D x F with K = 0.20. Preload F is calculated as 75% of proof strength times tensile stress area. A lubricated multiplier of 0.75 is applied to the dry value.
Yes, Bolt Torque Spec Calc is designed to work offline, making it suitable for use on the shop floor or in the field where internet access may be unavailable.
No, Bolt Torque Spec Calc is ad-free. The developer explicitly states 'No ads' as a benefit of using this application.
Bolt Torque Spec Calc costs $1.99 and offers lifetime access. This is a one-time purchase.
Bolt Torque Spec Calc is available for iPhone and iPad. It also supports Family Sharing for access on Mac.
The latest version, 1.0.5, was released on June 27, 2026, indicating recent updates. The app was initially released on March 23, 2026.
No, Bolt Torque Spec Calc is not a substitute for manufacturer-specified torque values for safety-critical fasteners. It uses a standard K factor and a general lubrication multiplier, and specific applications may require OEM-verified tightening specs.
