Bolt Tensile Capacity Calculator Online (Grade 8.8/10.9/12.9 Chart)

bolt Tensile Capacity Calculator (Grade 8.8/10.9/12.9 Chart)

The most basic sizing question for a bolt is "how much load can it actually carry". The online calculator on this page derives the ultimate tensile capacity from the effective thread area and property grade, with rough single/double shear estimates and an optional safety factor for allowable loads.

Tension capacity follows F = σb x As: σb is the tensile strength of the grade (800 MPa for 8.8, 1000 for 10.9, 1200 for 12.9) and As is the effective thread area. Shear is estimated on the shank area PI d^2/4 with shear strength of about 0.6σb, doubled for double shear. Real joints also involve preload, fatigue, engagement length and parent-material strength, so use a safety factor of 2 or higher for critical joints and verify by test.

Ultimate capacity is not allowable load: take 2.5-3 for dynamic or impact duty. Pair with our preload calculator for assembly settings. Zhuhai Jiali Hardware supplies grade 8.8/10.9/12.9 high-strength bolts with test reports - contact us.