What is shear strength of a bolt?

Shear strength is the maximum force a bolt can resist when the load acts perpendicular to the bolt axis, trying to slide one part of a joint past another. It is typically taken as about 60% of the bolt's ultimate tensile strength (Von Mises criterion).

What is the difference between single and double shear?

In single shear, one shear plane cuts through the bolt shank. In double shear (e.g., a clevis or lap joint with two outer plates), two shear planes act simultaneously, so the capacity is doubled.

What safety factor should I use?

A safety factor of 2.0 is common for static structural loads. Fatigue or dynamic applications often use 3.0 or higher. Always follow the applicable design code for your application.

What tensile strength values are used for each grade?

SAE Grade 2: 690 MPa, Grade 5: 830 MPa, Grade 8: 1030 MPa. ISO Class 4.6: 400 MPa, 8.8: 800 MPa, 10.9: 1040 MPa, 12.9: 1220 MPa. These are minimum specified ultimate tensile strengths per standard.

Does this account for thread stripping?

No. This calculator covers bolt shank shear only. Thread stripping and bearing stress in the mating part require separate checks, especially for short thread engagement.

Bolt Shear Strength Calculator

Name: Bolt Shear Strength Calculator
Availability: InStock
Author: Nham Vu

Calculate single- or double-shear bolt capacity from diameter, material grade, and safety factor.

Bolt Parameters

Bolt Standard

SAE (inch) ISO (metric)

Grade / Class

Nominal Bolt Diameter

Shear Type

Single shear Double shear

Safety Factor (applied to ultimate shear strength)

Shear Area

—

mm²

Ultimate Shear

—

Allowable Shear Load

—

Calculation Breakdown

Enter values and click Calculate.

Grade Reference

Grade	UTS (MPa)	Shear (MPa)

Summary

Calculate single- or double-shear bolt capacity from diameter, material grade, and safety factor.

How it works

Select the bolt standard (SAE or ISO) and choose a grade or class.
Enter the nominal bolt diameter and select the diameter unit (mm or inches).
Choose single or double shear based on your joint configuration.
Set a safety factor (default 2.0 is typical for structural applications).
Click Calculate to see allowable shear load and shear area.

Use cases

Sizing bolts for steel structural connections.
Verifying fastener capacity in machine frames and brackets.
Comparing SAE vs. ISO bolt grades for a given load requirement.
Checking double-shear clevis joints in mechanical linkages.
Quick design checks before detailed FEA analysis.

Frequently Asked Questions

Last updated: 2026-06-10 · Reviewed by Nham Vu