What does this bolt shear estimate use?

It applies the AISC 360 threaded-part nominal shear-stress factors to the selected minimum tensile strength: 0.450 Fu when threads cross the shear plane and 0.563 Fu when threads are excluded. This is a screening estimate, not a complete connection design.

What is the difference between single and double shear?

Single shear has one potential shear plane; double shear has two. This calculator doubles bolt-only nominal area for two planes, but bearing, tear-out, eccentricity, unequal load distribution and connected-part strength can prevent the whole joint from gaining exactly twice the usable capacity.

What safety factor should I use?

Use the factor and resistance format required by the governing code, load combination and application. The default 2.0 is only a worked-example input and is not a universal structural recommendation.

What tensile strength values are used for each grade?

Within the supported SAE J429 size range, Grade 2 uses 510 MPa through 3/4 inch and 414 MPa above 3/4 inch; Grade 5 uses 830 MPa through 1 inch and 724 MPa above 1 inch; Grade 8 uses 1030 MPa. ISO classes use the displayed base values. Confirm the applicable product standard, diameter range and certification before design.

Does this complete a bolted-joint design?

No. It does not check bearing, tear-out, net-section rupture, block shear, slip, preload, combined tension and shear, fatigue, eccentric bolt groups, thread stripping, hole type or code resistance factors. A qualified engineer must check the full connection.

Bolt Shear Strength Calculator

Estimate per-bolt single- or double-shear capacity, with separate AISC factors for threads included in or excluded from the shear plane.

Bolt Parameters

Bolt Standard

SAE (inch) ISO (metric)

Grade / Class

Nominal Bolt Diameter

Shear Type

Single shear Double shear

Threads at Shear Plane Included — conservative default; plane crosses threads Excluded — plane is proven to cross full shank only

Safety Factor (applied to ultimate shear strength)

Shear Area

—

mm² total

Ultimate Shear

—

Allowable Shear Load

—

Screening estimate only. The bolt-only result does not establish connection capacity. Check the governing code and all connected-part, hole, bearing, tear-out, slip, fatigue, tension interaction and load-distribution limit states.

Method & sources

AISC 360 Table J3.2 gives generic threaded-part nominal shear stress as 0.450 Fu with threads included and 0.563 Fu with threads excluded. Results use gross nominal shank area and the selected number of planes.

AISC 360 specification and commentary · AISC bolting FAQs

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Calculation Breakdown

Enter values and click Calculate.

Grade Reference

Grade	UTS (MPa)	N: 0.450 Fu	X: 0.563 Fu

Summary

Estimate per-bolt single- or double-shear capacity, with separate AISC factors for threads included in or excluded from the shear plane.

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 and state whether threads cross the shear plane.
Enter the safety factor required by your design basis (the default is an example, not a code selection).
Click Calculate to see the nominal estimate and the value after your entered factor.

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: 2026-09-20 · Reviewed by Nham Vu