By Zencalcy Editorial TeamLast reviewed About us
A thread is defined by its nominal diameter and pitch, and those two numbers generate every other dimension. This calculator gives the basic pitch and minor diameters, the tensile stress area, and the load a bolt of a given property class can carry.
Metric thread dimensions and tensile capacity.
d₂ = d − 0.6495P As = π/4 (d − 0.9382P)² F = As × tensile strength
Property class 8.8 has 800 MPa tensile and 640 MPa proof; 10.9 has 1,000 and 940; 12.9 has 1,220 and 1,100. Use the proof load for a safe working figure and apply a joint-specific safety factor.
| Symbol | Meaning |
|---|---|
| d, P | Nominal diameter and pitch. |
| As | Tensile stress area. |
| F | Tensile capacity. |
Stress area 58.0 mm² × 640 MPa proof = 37.1 kN, or about 8,300 lb.
Continue with the Beam Deflection Calculator, Beam Load Calculator, Bending Stress Calculator, or the Wood Beam Span Calculator — or browse more structural & workshop and all construction calculators.
Coarse is standard and more resistant to damage; fine pitch gives more preload and is used in vibration or thin-wall applications.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026