Metal stud sizes are written as a single code such as 362S162-33. That string tells you the web depth, the section type, the flange width, and the steel thickness, in that order. Once you can read it, the whole catalog becomes obvious and you stop needing to look sizes up. This page explains the code, gives the thickness and gauge conversions, and lists the standard depths and flange widths.
How to Read 362S162-33
The Steel Stud Manufacturers Association (SSMA) designation has four parts. The trick to the numbers is that they are in hundredths of an inch, not sixteenths and not millimeters.
| Part | Example | Meaning |
|---|---|---|
| Web depth | 362 | 362/100 in = 3-5/8 in deep |
| Style | S | Stud or joist section |
| Flange width | 162 | 162/100 in = 1-5/8 in flange |
| Mil thickness | 33 | 33 mils = 0.033 in minimum base steel |
So 362S162-33 is a 3-5/8 in deep stud with a 1-5/8 in flange in 33 mil steel. A 600S162-54 is a 6 in deep stud, same flange, in heavier 54 mil steel. The system is the same idea as reading steel beam sizes, except the numbers are dimensions rather than weight per foot.
The Four Style Letters
| Letter | Section | What it is |
|---|---|---|
| S | Stud or joist | The C-shaped member with stiffening lips on the flanges |
| T | Track | The plain U-shaped channel the studs sit in, top and bottom |
| U | Channel | Cold-rolled channel, used for bracing and bridging |
| F | Furring channel | Hat-shaped section for furring out a wall or ceiling |
One detail catches people out when ordering: for T sections the member depth is the inside-to-inside dimension, not the outside. Track is meant to receive studs, so it is sized by the opening. That is why a 362T125 track fits a 362S162 stud rather than being a loose or tight fit. It also means you cannot compare an S depth and a T depth as if they were measured the same way.
Mils, Gauge and Design Thickness
The industry moved off gauge numbers to mils, where one mil is one thousandth of an inch, because gauge was never a unit of anything. Suppliers still quote gauge in conversation, so this is the table that matters. The color code is a mill marking used to identify thickness on site.
| Mils | Minimum thickness (in) | Design thickness (in) | Former gauge | Color code |
|---|---|---|---|---|
| 33 | 0.033 | 0.0346 | 20 (structural) | White |
| 43 | 0.043 | 0.0451 | 18 | Yellow |
| 54 | 0.054 | 0.0566 | 16 | Green |
| 68 | 0.068 | 0.0713 | 14 | Orange |
| 97 | 0.097 | 0.1017 | 12 | Red |
| 118 | 0.118 | 0.1242 | 10 | Blue |
There are two thicknesses because they serve different purposes. Design thickness is what an engineer calculates with. Minimum thickness is what has to actually show up on the truck, and it is defined as 95 percent of the design thickness. You can verify every row: 33 ÷ 0.95 = 34.7 mils, which is the 0.0346 in design thickness. 97 ÷ 0.95 = 102.1, giving 0.1017. The mil number in the designation is the minimum, so a 33 mil stud is guaranteed to be at least 0.033 in thick.
Note that these are base steel thicknesses, measured before any galvanized coating. That is the same convention used for sheet steel gauge generally, and it is why a coated stud measures slightly over its nominal thickness with calipers.
Standard Depths and Flange Widths
Depths available as standard: 1-5/8, 2-1/2, 3-5/8, 4, 6, 8, 10, 12, 14 and 16 in. Flange widths: 1-1/4, 1-3/8, 1-5/8, 2, 2-1/2, 3 and 3-1/2 in.
In practice a small number of combinations do most of the work:
| Designation | Depth | Typical use |
|---|---|---|
| 162S125-18 | 1-5/8 in | Furring, shallow partitions, soffits |
| 250S162-33 | 2-1/2 in | Interior non-load-bearing partitions |
| 362S162-33 | 3-5/8 in | The default interior partition stud |
| 400S162-33 | 4 in | Partitions needing more depth for services |
| 600S162-43 | 6 in | Tall partitions, shaft walls, light exterior framing |
| 600S162-54 | 6 in | Load-bearing and exterior curtain wall studs |
| 800S200-68 | 8 in | Load-bearing walls, long spans, joists |
The 3-5/8 in stud is dominant indoors for a reason unrelated to structure: it plus two layers of 1/2 in board lands a partition at about 4-5/8 in, and 3-5/8 in is the depth that suits standard electrical boxes and single-stud plumbing runs.
Structural vs Non-Structural
This is the distinction that matters most on a submittal, and the designation alone does not always make it obvious. Non-structural studs, sometimes called drywall studs, carry only the wall itself and the loads applied to its face. Structural studs carry axial load from above, or larger lateral loads, and are designed as cold-formed steel members.
Thickness is the usual dividing line in conversation, with 33 mil and lighter treated as non-structural and 43 mil and heavier as structural, but that is a rule of thumb rather than a definition. Steel yield strength is the sharper issue. Some sections are produced in both 33 ksi and 50 ksi steel, and the two look identical. If a design relies on 50 ksi material, the yield strength has to be called out explicitly on the drawings and on the order, written as 600S162-54 (50 ksi). Leave it off and there is nothing stopping 33 ksi studs arriving, which will be legitimate against the designation and inadequate against the calculation.
Punchouts, Bend Radius and Section Properties
Studs come with web punchouts for services. Two consequences follow. First, published gross section properties are calculated on the full unreduced cross section away from the punchouts, so they do not describe the section at a hole. Second, the punchouts are located and sized on a standard pattern, and cutting your own holes, or enlarging one, invalidates the tabulated capacity.
Two more details govern the published numbers. The centerline bend radius is the greater of twice the design thickness or 3/32 in, which is what makes the corners of a thin stud noticeably rounder than a rolled shape. And for deflection calculations you use the effective moment of inertia rather than the gross value, because a thin web does not stay fully effective in compression. Cold-formed sections also pick up a strength increase from the cold work of forming, which is accounted for in the effective properties, not the gross ones.
All of which is to say: for anything carrying load, take the properties from the manufacturer’s current table for the exact section and yield strength, and read the footnotes. Unlike hot-rolled shapes in the wide flange beam sizes chart, a cold-formed stud has several different sets of properties depending on what you are checking.
Metal Stud Sizes FAQ
What does the S in 362S162 mean?
Stud or joist section, meaning the C-shaped member with stiffening lips on its flanges. T is track, U is cold-rolled channel, F is furring channel.
Is a 25 gauge stud the same as 18 mil?
Roughly, and that is the problem with gauge. 18 mil is 0.018 in minimum. Gauge numbers were never standardized across products, which is exactly why SSMA replaced them with a direct thickness in mils. Order by mils.
What size metal stud for a 10 ft wall?
There is no single answer, because height alone does not determine it. Stud spacing, the lateral load, the deflection limit the finish requires, and whether the wall carries anything above all change the result. A limiting height table from the manufacturer for the exact section and yield strength is the correct tool.
Why is the flange width the same on so many sizes?
A 1-5/8 in flange suits standard screw patterns and board fixing, so it is kept constant while depth changes. Wider flanges, 2 in and up, appear on load-bearing and joist sections where the flange has to resist more compression.
Sources: SSMA Product Technical Information (Steel Stud Manufacturers Association) for the designation system, style letters, track depth convention, yield strength callout, bend radius and section property table notes; Marino\WARE steel framing nomenclature for the mil, design thickness, gauge and color code table and the standard depth and flange ranges. Last updated: September 2026.
This page is reference information only and is not engineering advice. Do not size load-bearing or exterior studs from it. Full disclaimer.