Tensile Thread Stress Area Equation and Calculator - 180 Ultimate Tensile Strength ksi and More

Standard ANSI Hardware
Fastener - Bolt Design Calculations

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This calculator calculates the tensile stress area of a external screw thread of a fastener. Use this calculator for materials over 180,000 psi ultimate tensile strength.

Open Calculator

This calculator will calculate the unknown for the given conditions. Two (2) inputs are required, See the application illustration at bottom of page.

Thread Stress Area


At = Tensile Strength Area of Screw Thread.
Esmin = MinimumPitch Diameter of External Thread - Thread Engineering Data Chart
n = Number of threads per inch

This equation is a more conservative extimation of actual thread stress area as opposed to the equation for Tensile Thread Stress Area 100 ksi and Less.

Bolt thread representation

Example; For a 1/2 - 13 UNC - 2A, see Thread Engineering Data Chart for minimum pitch diameter data.

Esmin = .4435
n = 13

At = 3.1416 (.4435/2 - 0.16238/13)2
At = .13757 = (Thread Stress Area)


Machinerys Handbook, 30th Edition