Aluminum gauge converter: gauge to inches and mm
Pick a gauge to get its thickness in inches and millimeters and its weight per square foot, or enter a thickness to get the nearest gauge and the difference. It uses the Brown & Sharpe (AWG) scale of ASTM B258, the one most used for aluminum in North America: 24 gauge is 0.0201 in (0.51 mm), 22 gauge 0.0253 in (0.64 mm) and 18 gauge 0.0403 in (1.02 mm).
The Brown & Sharpe formula
The Brown & Sharpe scale, also called AWG, is defined in ASTM B258 and was made for wire. Gauge n is 0.005 × 92^((36 − n) ÷ 39) inches thick; times 25.4 gives millimeters. Each gauge is about 11% thinner than the one before, and every six gauges the thickness drops by about half. Inches are rounded to four decimals, as printed charts do, and millimeters and weight are calculated from there.
Aluminum gauge chart, 6 to 30
Thickness in inches and millimeters, theoretical weight per square foot at 2.71 g/cm³ (0.0979 lb/in³), and the form in which Almexa makes each gauge per its September 2026 technical sheet.
| Gauge | Inches | Millimeters | lb/ft² (kg/m²) | Almexa makes it as |
|---|---|---|---|---|
| 6 | 0.1620 | 4.11 | 2.284 (11.15) | Plate (0.157 to 13 in) |
| 7 | 0.1443 | 3.67 | 2.034 (9.93) | Coil, strip, sheet and circles |
| 8 | 0.1285 | 3.26 | 1.812 (8.85) | Coil, strip, sheet and circles |
| 9 | 0.1144 | 2.91 | 1.613 (7.87) | Coil, strip, sheet and circles |
| 10 | 0.1019 | 2.59 | 1.437 (7.01) | Coil, strip, sheet and circles |
| 11 | 0.0907 | 2.30 | 1.279 (6.24) | Coil, strip, sheet and circles |
| 12 | 0.0808 | 2.05 | 1.139 (5.56) | Coil, strip, sheet and circles |
| 13 | 0.0720 | 1.83 | 1.015 (4.96) | Coil, strip, sheet and circles |
| 14 | 0.0641 | 1.63 | 0.904 (4.41) | Coil, strip, sheet and circles |
| 15 | 0.0571 | 1.45 | 0.805 (3.93) | Coil, strip, sheet and circles |
| 16 | 0.0508 | 1.29 | 0.716 (3.50) | Coil, strip, sheet and circles |
| 17 | 0.0453 | 1.15 | 0.639 (3.12) | Coil, strip, sheet and circles |
| 18 | 0.0403 | 1.02 | 0.568 (2.77) | Coil, strip, sheet and circles |
| 19 | 0.0359 | 0.91 | 0.506 (2.47) | Coil, strip, sheet and circles |
| 20 | 0.0320 | 0.81 | 0.451 (2.20) | Coil, strip, sheet and circles |
| 21 | 0.0285 | 0.72 | 0.402 (1.96) | Coil, strip, sheet and circles |
| 22 | 0.0253 | 0.64 | 0.357 (1.74) | Coil, strip, sheet and circles |
| 23 | 0.0226 | 0.57 | 0.319 (1.56) | Coil, strip, sheet and circles |
| 24 | 0.0201 | 0.51 | 0.283 (1.38) | Coil, strip and sheet |
| 25 | 0.0179 | 0.45 | 0.252 (1.23) | Coil and strip, 1000 and 3000 series |
| 26 | 0.0159 | 0.40 | 0.224 (1.09) | Not today (from 0.0177 in) |
| 27 | 0.0142 | 0.36 | 0.200 (0.98) | Not today (from 0.0177 in) |
| 28 | 0.0126 | 0.32 | 0.178 (0.87) | Not today (from 0.0177 in) |
| 29 | 0.0113 | 0.29 | 0.159 (0.78) | Not today (from 0.0177 in) |
| 30 | 0.0100 | 0.25 | 0.141 (0.69) | Not today (from 0.0177 in) |
What gauges Almexa makes
Per its September 2026 technical sheet, Almexa rolls coil and strip from 0.0177 to 0.1575 in (0.45 to 4.0 mm; from 0.0197 in in 5000 series), cuts sheet from 0.0197 to 0.1575 in (0.5 to 4.0 mm) and blanks circles from 0.0220 to 0.1575 in (0.56 to 4.0 mm). On the Brown & Sharpe scale that is 25 to 7 gauge in coil and strip, 24 to 7 in sheet and 23 to 7 in circles. The 0.1575 in maximum falls between 7 gauge (0.1443 in) and 6 gauge (0.1620 in); above 0.157 in, Almexa makes plate from 0.157 to 13 in (4 to 330 mm). Gauges 26 to 30 are thinner than 0.0177 in and are not made today; with the equipment being installed, coil will go down to 0.0118 in (0.3 mm) by the end of 2027.
Related tools and guides
- Aluminum sheet gauge chart: inches, millimeters and weight which gauge fits facades, ducts, stamping and cookware
- Aluminum sheet weight calculator pounds per sheet and sheets per ton
- Aluminum circles per ton weight per circle by diameter and thickness
- Weight calculator coil, sheet and circle to kilograms
- Aluminum sheet and plate sheet 0.0197 to 0.1575 in, plate 0.157 to 13 in
- Aluminum coil 0.0177 to 0.1575 in
- Request a quote order thickness in decimal inches or millimeters with its tolerance
Sources
- ASTM B258-18 (reapproved 2026): standard nominal diameters of AWG sizes Brown & Sharpe scale; accessed October 22, 2026
Manufacturing ranges: Almexa technical sheet, September 2026. Density of 2.71 g/cm³ (0.0979 lb/in³), the same every calculator on this site uses.
Frequently asked questions
How thick is 24 gauge aluminum?
0.0201 in, or 0.51 mm, on the Brown & Sharpe (AWG) scale. It weighs about 0.283 lb/ft² (1.38 kg/m²) at 2.71 g/cm³. Almexa makes it in coil, strip and sheet; circles start at 0.0220 in (0.56 mm), close to 23 gauge.
How do you convert aluminum gauge to inches?
With the Brown & Sharpe (AWG) formula in ASTM B258: inches = 0.005 × 92^((36 − gauge) ÷ 39), and millimeters = inches × 25.4. For example, 22 gauge gives 0.0253 in, that is 0.64 mm.
Is gauge an official measure for aluminum sheet?
No. No standard sets gauge for aluminum sheet and other charts differ in the second decimal, so the same number can mean two different thicknesses. Order thickness in decimal inches or millimeters with its tolerance; gauge is only for conversation.
What aluminum gauges does Almexa make?
25 to 7 gauge in coil and strip (0.0177 to 0.1575 in; 25 gauge only in 1000 and 3000 series), 24 to 7 in sheet (0.0197 to 0.1575 in) and 23 to 7 in circles (0.0220 to 0.1575 in), per the September 2026 technical sheet. 6 gauge is 0.1620 in (4.11 mm) and falls in plate, which runs 0.157 to 13 in.
Send thickness in decimal inches or millimeters and the tolerance you need. We quote from the plant.
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