Thickness Tolerances

Common Flat Rolled Steel Calculations

Businesses engaged in the buying and selling of steel must understand steel gauges and tolerance ranges. These tolerances are based off of a combination of standards: SMACNA, ASTM, and mill specifications.

For a listing of product tolerances, click on the product links on the right of your screen.

When purchasing steel from a domestic steel mill, foreign steel mill or distributor there are standards and guidelines for what are acceptable tolerances (variations in the actual thickness of the steel) by product.  For each item purchased there are minimum thickness requirements as well as maximum allowable variations.

In the "real world" flat rolled steel is sold by decimal and/or by numerical whole gauge numbers. In this section we provide details for the most used tolerances on hot rolled, cold rolled and galvanized steels. The tables for each product can be accessed by clicking on the links shown in the right hand column on this page.

Gage - Manufactures standard gage. Shown here aligned to ASTM decimal tolerances.

Min.  -   The minimum ASTM decimal tolerance in the gauge range.

Max. -   The maximum ASTM decimal tolerance in the gauge range .

Nom. -  The nominal or midpoint in the ASTM tolerance range.