Steel Gauge to Decimal Conversion Chart
Sheet steel is specified by gauge number, but drawings, tolerances, and purchasing specifications are written in decimal inches. This chart converts between the two for hot rolled, pickled and oiled, and cold rolled carbon steel sheet.
A lower gauge number means thicker material. Gauge numbers are not consistent across materials — the same gauge represents a different thickness in stainless, aluminum, and galvanized steel. The values below apply to carbon steel sheet only.
Hot Rolled, P&O, and Cold Rolled Steel
Thickness in inches.
| Gauge | Decimal Equivalent | Tolerance Range: Hot Rolled P&O | Tolerance Range: Cold Rolled | Lbs. per Square Foot |
|---|---|---|---|---|
| 3 | 0.239 | .229 to .249 | — | 10.000 |
| 4 | 0.224 | .214 to .234 | — | 9.375 |
| 5 | 0.209 | .199 to .219 | — | 8.750 |
| 6 | 0.194 | .184 to .204 | — | 8.125 |
| 7 | 0.179 | .171 to .187 | — | 7.500 |
| 8 | 0.164 | .156 to .172 | — | 6.875 |
| 9 | 0.149 | .141 to .157 | — | 6.250 |
| 10 | 0.134 | .126 to .142 | .128 to .140 | 5.625 |
| 11 | 0.120 | .112 to .128 | .114 to .126 | 5.000 |
| 12 | 0.105 | .097 to .113 | .099 to .112 | 4.375 |
| 13 | 0.090 | .083 to .097 | .085 to .095 | 3.750 |
| 14 | 0.075 | .068 to .082 | .070 to .080 | 3.125 |
| 15 | 0.067 | .060 to .075 | .062 to .072 | 2.812 |
| 16 | 0.060 | .053 to .067 | .055 to .065 | 2.500 |
| 17 | 0.054 | .048 to .060 | .050 to .058 | 2.250 |
| 18 | 0.048 | — | .044 to .052 | 2.000 |
| 19 | 0.042 | — | .038 to .046 | 1.750 |
| 20 | 0.036 | — | .033 to .039 | 1.500 |
| 21 | 0.033 | — | .030 to .036 | 1.375 |
| 22 | 0.030 | — | .027 to .033 | 1.250 |
| 23 | 0.027 | — | .024 to .030 | 1.125 |
| 24 | 0.024 | — | .021 to .027 | 1.000 |
| 25 | 0.021 | — | .018 to .024 | 0.875 |
| 26 | 0.018 | — | .016 to .020 | 0.750 |
| 27 | 0.016 | — | .014 to .018 | 0.688 |
| 28 | 0.015 | — | .013 to .017 | 0.625 |
| 29 | 0.014 | — | — | 0.562 |
| 30 | 0.012 | — | — | 0.500 |
How to Use This Chart
Decimal equivalent is the nominal thickness for that gauge.
Tolerance range is the acceptable thickness variation as produced. Hot rolled and P&O carry a wider tolerance than cold rolled, which is one reason cold rolled costs more. If your part depends on consistent thickness, the tolerance column matters more than the nominal.
Lbs. per square foot lets you estimate material weight for a blank or a finished part — useful for freight, handling, and comparing material cost between gauges.
Where the ranges are blank, that gauge is not typically produced in that process. Hot rolled generally runs heavier, cold rolled generally runs lighter, and they overlap between 10 and 17 gauge.
A Note on Gauge Numbers
Gauge is a legacy system, and it isn't consistent across materials. 16 gauge carbon steel is 0.060". 16 gauge stainless is 0.0625". 16 gauge aluminum is 0.0508". A drawing that specifies a gauge without naming the material is ambiguous, and that ambiguity causes real problems on parts where thickness is functional.
For anything critical, specify the decimal thickness rather than the gauge number.
Sourcing sheet steel?
Chapman Smith supplies hot rolled, cold rolled, galvanized, and aluminized steel in coils and blanks, along with stainless flat rolled and wire. Send us a specification and we'll quote it.