Thread Calculator
Calculate thread dimensions from any diameter and pitch. Uses ISO 724 formulas for 60° threads (metric, UNC, UNF).
Calculated Dimensions
Formulas Used (ISO 724 / ASME B1.1)
H = (√3/2) × P — Fundamental triangle height
d₂ = d − 0.6495 × P — Pitch diameter
d₁ = d − 1.2269 × P — Minor diameter (external)
D₁ = d − 1.0825 × P — Minor diameter (internal / tap drill)
Aₛ = (π/4) × ((d₂ + d₃)/2)² — Tensile stress area, where d₃ = d₁ − H/6
Frequently Asked Questions
How is tensile stress area calculated?
Tensile stress area is calculated as As = (pi/4) × ((d2 + d3)/2)², where d2 is the pitch diameter and d3 = d1 - H/6 (d1 = d - 1.0825P is the basic minor diameter, H is the fundamental triangle height). This is per ISO 898-1. For unified inch threads, the calculator uses the ASME B1.1 formula As = 0.7854 × (D - 0.9743/n)², where n is threads per inch.
What formulas does this calculator use?
This calculator uses ISO 724 formulas for metric threads and ASME B1.1 for unified inch threads. Pitch diameter: d2 = d - 0.6495P. Minor diameter: d1 = d - 1.2269P. Thread depth: 5H/8 where H = (sqrt(3)/2) × P.