Steel
The Manufacturers' Standard Gauge, defined by weight per square foot. 16 gauge is 2.5 lb per square foot, which works out at 0.0598 in.
Workshop reference
Sheet Metal Gauge Chart
Every gauge from 7 to 30 in inches and millimeters for steel, galvanized, stainless and aluminum, with the weight of sheet steel per square foot.
The short answer
16 gauge steel is 0.0598 in (1.52 mm) thick, 14 gauge is 0.0747 in (1.90 mm) and 10 gauge is 0.1345 in (3.42 mm). A higher gauge number means thinner metal, and the same number is a different thickness in stainless, galvanized and aluminum.
Sheet metal gauge to inches
The thickness of each gauge in decimal inches, the form the US standards publish. Read across to the column for the metal you are buying: 16 gauge is 0.0598 in steel but 0.0508 in aluminum.
| Gauge | Steel (in) | Galvanized (in) | Stainless (in) | Aluminum (in) |
|---|---|---|---|---|
| 7 | 0.1793 | - | 0.1875 | 0.1443 |
| 8 | 0.1644 | 0.1681 | 0.1719 | 0.1285 |
| 9 | 0.1495 | 0.1532 | 0.1563 | 0.1144 |
| 10 | 0.1345 | 0.1382 | 0.1406 | 0.1019 |
| 11 | 0.1196 | 0.1233 | 0.1250 | 0.0907 |
| 12 | 0.1046 | 0.1084 | 0.1094 | 0.0808 |
| 13 | 0.0897 | 0.0934 | 0.0938 | 0.0720 |
| 14 | 0.0747 | 0.0785 | 0.0781 | 0.0641 |
| 15 | 0.0673 | 0.0710 | 0.0703 | 0.0571 |
| 16 | 0.0598 | 0.0635 | 0.0625 | 0.0508 |
| 18 | 0.0478 | 0.0516 | 0.0500 | 0.0403 |
| 20 | 0.0359 | 0.0396 | 0.0375 | 0.0320 |
| 22 | 0.0299 | 0.0336 | 0.0313 | 0.0253 |
| 24 | 0.0239 | 0.0276 | 0.0250 | 0.0201 |
| 26 | 0.0179 | 0.0217 | 0.0188 | 0.0159 |
| 28 | 0.0149 | 0.0187 | 0.0156 | 0.0126 |
| 30 | 0.0120 | 0.0157 | 0.0125 | 0.0100 |
A hyphen means that metal is not made as a standard sheet at that gauge. Mills roll to a tolerance either side of these figures, so measure with calipers when the fit matters.
Sheet metal gauge to mm
The same gauges in millimeters, converted from the published inch figures at exactly 25.4 mm to the inch. For quick shop talk, 16 gauge steel is 1.5 mm, 14 gauge is 1.9 mm and 10 gauge is 3.4 mm.
| Gauge | Steel (mm) | Galvanized (mm) | Stainless (mm) | Aluminum (mm) |
|---|---|---|---|---|
| 7 | 4.554 | - | 4.763 | 3.665 |
| 8 | 4.176 | 4.270 | 4.366 | 3.264 |
| 9 | 3.797 | 3.891 | 3.970 | 2.906 |
| 10 | 3.416 | 3.510 | 3.571 | 2.588 |
| 11 | 3.038 | 3.132 | 3.175 | 2.305 |
| 12 | 2.657 | 2.753 | 2.779 | 2.053 |
| 13 | 2.278 | 2.372 | 2.383 | 1.828 |
| 14 | 1.897 | 1.994 | 1.984 | 1.628 |
| 15 | 1.709 | 1.803 | 1.786 | 1.450 |
| 16 | 1.519 | 1.613 | 1.588 | 1.291 |
| 18 | 1.214 | 1.311 | 1.270 | 1.024 |
| 20 | 0.912 | 1.006 | 0.953 | 0.812 |
| 22 | 0.759 | 0.853 | 0.795 | 0.644 |
| 24 | 0.607 | 0.701 | 0.635 | 0.511 |
| 26 | 0.455 | 0.551 | 0.478 | 0.405 |
| 28 | 0.378 | 0.475 | 0.396 | 0.321 |
| 30 | 0.305 | 0.399 | 0.318 | 0.255 |
How much does sheet steel weigh by gauge?
The US steel gauge is defined by weight, not by thickness: each gauge is a set weight per square foot, and the thickness follows from 41.82 lb per square foot for every inch of steel. That makes the weight column exact. A 4 x 8 ft sheet is 32 square feet.
| Gauge | Thickness (in) | lb per sq ft | kg per sq m | 4 x 8 ft sheet (lb) |
|---|---|---|---|---|
| 7 | 0.1793 | 7.5 | 36.62 | 240 |
| 8 | 0.1644 | 6.875 | 33.57 | 220 |
| 9 | 0.1495 | 6.25 | 30.52 | 200 |
| 10 | 0.1345 | 5.625 | 27.46 | 180 |
| 11 | 0.1196 | 5 | 24.41 | 160 |
| 12 | 0.1046 | 4.375 | 21.36 | 140 |
| 13 | 0.0897 | 3.75 | 18.31 | 120 |
| 14 | 0.0747 | 3.125 | 15.26 | 100 |
| 15 | 0.0673 | 2.8125 | 13.73 | 90 |
| 16 | 0.0598 | 2.5 | 12.21 | 80 |
| 18 | 0.0478 | 2 | 9.76 | 64 |
| 20 | 0.0359 | 1.5 | 7.32 | 48 |
| 22 | 0.0299 | 1.25 | 6.10 | 40 |
| 24 | 0.0239 | 1 | 4.88 | 32 |
| 26 | 0.0179 | 0.75 | 3.66 | 24 |
| 28 | 0.0149 | 0.625 | 3.05 | 20 |
| 30 | 0.0120 | 0.5 | 2.44 | 16 |
Plain carbon steel. Galvanized sheet adds the zinc, about 0.16 lb per square foot at every gauge. Stainless weighs within a couple of percent of carbon steel of the same thickness, and aluminum about a third.
Why does a higher gauge mean thinner metal?
Gauge numbers come from wire drawing, where each pass through a smaller die took the wire down a size and added one to the count. More passes meant thinner wire and a bigger number, and sheet metal kept the same direction. That is why 20 gauge is thinner than 10 gauge.
The catch is that there was never one gauge. Each metal settled on its own series, so a gauge number is a lookup, not a measurement, and it means nothing until you say which metal.
Galvanized
The steel gauge plus an allowance for the zinc, about 0.0037 in. 16 gauge galvanized is 0.0635 in. There is no standard 7 gauge.
Stainless
A fractional inch series: 16 gauge is exactly 1/16 in (0.0625), 11 gauge is 1/8 in and 7 gauge is 3/16 in. Some suppliers run a few thousandths thinner, so check the mill certificate.
Aluminum
Brown and Sharpe, the same series as AWG wire, worked out from a formula. It is the thinnest of the four at every gauge: 16 gauge is 0.0508 in.
Where does gauge stop and plate start?
Around 7 gauge. Past about 3/16 in, US mills and stockholders sell steel by its fraction of an inch (1/4, 5/16, 3/8) rather than by gauge. If a drawing calls for 3/16 plate, 7 gauge sheet at 0.1793 in is close but not the same thing.
Is SWG the same as US gauge?
No. The British Standard Wire Gauge (SWG), made a legal standard in 1884, gives different thicknesses for the same numbers. 16 SWG is 1.626 mm while 16 gauge US steel is 1.519 mm. UK stockholders now sell sheet by its thickness in millimeters, so SWG mostly turns up on older drawings and in trade talk. When a UK and a US drawing both say 16 gauge, check which one they mean.
| Gauge | SWG (in) | SWG (mm) | US steel (mm) |
|---|---|---|---|
| 7 | 0.176 | 4.470 | 4.554 |
| 8 | 0.160 | 4.064 | 4.176 |
| 9 | 0.144 | 3.658 | 3.797 |
| 10 | 0.128 | 3.251 | 3.416 |
| 11 | 0.116 | 2.946 | 3.038 |
| 12 | 0.104 | 2.642 | 2.657 |
| 13 | 0.092 | 2.337 | 2.278 |
| 14 | 0.080 | 2.032 | 1.897 |
| 15 | 0.072 | 1.829 | 1.709 |
| 16 | 0.064 | 1.626 | 1.519 |
| 18 | 0.048 | 1.219 | 1.214 |
| 20 | 0.036 | 0.914 | 0.912 |
| 22 | 0.028 | 0.711 | 0.759 |
| 24 | 0.022 | 0.559 | 0.607 |
| 26 | 0.0180 | 0.457 | 0.455 |
| 28 | 0.0148 | 0.376 | 0.378 |
| 30 | 0.0124 | 0.315 | 0.305 |
Sheet metal gauge questions
The ones that come up at the shear and on the phone to the stockholder, answered with the numbers.
How thick is 16 gauge steel?
16 gauge steel is 0.0598 in (1.52 mm) thick. The same gauge number means something different in other metals: 16 gauge stainless is 0.0625 in (1.59 mm), 16 gauge aluminum is 0.0508 in (1.29 mm) and 16 gauge galvanized is 0.0635 in (1.61 mm).
Which is thicker, 14 gauge or 16 gauge?
14 gauge. With sheet metal gauges a lower number is thicker metal, so 14 gauge steel is 0.0747 in (1.90 mm) against 0.0598 in (1.52 mm) for 16 gauge. The same holds for 16 against 18 gauge, and 10 against 12.
How thick is 14 gauge steel?
14 gauge steel is 0.0747 in (1.90 mm) thick. 14 gauge stainless is 0.0781 in (1.98 mm) and 14 gauge aluminum is 0.0641 in (1.63 mm).
How thick is 10 gauge steel?
10 gauge steel is 0.1345 in (3.42 mm) thick, and 11 gauge is 0.1196 in (3.04 mm). 10 gauge weighs 5.625 lb per square foot, so a 4 x 8 ft sheet is about 180 lb.
What gauge is 1/8 inch steel?
11 gauge is the nearest standard gauge to 1/8 inch (0.125 in). 11 gauge steel is 0.1196 in (3.04 mm), a little under 1/8. In stainless the fractional series makes 11 gauge exactly 1/8 inch, 0.1250 in (3.17 mm).
What gauge is 3/16 inch steel?
7 gauge, which is 0.1793 in (4.55 mm) in steel and exactly 3/16 inch, 0.1875 in (4.76 mm), in stainless. Anything thicker is normally sold as plate by its fraction of an inch rather than by gauge.
How much does 16 gauge steel weigh?
16 gauge steel weighs 2.5 lb per square foot (12.21 kg per square meter). A 4 x 8 ft sheet is 32 square feet, so it weighs about 80 lb.
Is aluminum gauge the same as steel gauge?
No. Aluminum uses the Brown and Sharpe series, the same one as AWG wire, and it runs thinner than steel at every gauge: 16 gauge aluminum is 0.0508 in (1.29 mm) against 0.0598 in (1.52 mm) for steel. Always read the column for the metal you are buying.
Why is galvanized steel thicker than plain steel at the same gauge?
The galvanized gauge adds an allowance for the zinc coating, about 0.0037 in at every gauge. So 16 gauge galvanized is 0.0635 in (1.61 mm) against 0.0598 in (1.52 mm) for bare steel. There is no standard 7 gauge galvanized sheet.
What is 16 gauge in mm?
16 gauge is 1.52 mm in steel, 1.59 mm in stainless, 1.29 mm in aluminum and 1.61 mm in galvanized steel. In the old British SWG system, 16 gauge is 1.63 mm, which is why UK and US drawings that say 16 gauge can disagree.
Where these numbers come from
Steel is the Manufacturers' Standard Gauge, galvanized is the US galvanized sheet gauge, stainless is the fractional inch series and aluminum is Brown and Sharpe, calculated from its formula rather than typed in. The inch figures are the published values and the millimeters are converted at exactly 25.4. The same table is built into Fabora Steel Tools, and it was checked against five independent published charts.
Gauges are nominal. Mills roll to a tolerance, and coatings add to the total, so for a critical fit measure the sheet you actually have.
Fabora Steel Tools
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