Convert sheet metal gauge to thickness in mm and inches for any metal — MS steel, GI sheet, stainless steel, aluminium, copper, and brass. Supports USG (US Standard Gauge) and B&S (Brown & Sharp) gauge systems with side-by-side multi-metal comparison.
Three modes — Gauge to mm, mm to nearest Gauge, and Side-by-Side Multi-Metal comparison at the same gauge number
Enter one gauge number to instantly see the thickness for all six metals — reveals why the same gauge number means very different thicknesses across metals.
Full gauge charts for all metals — select tab to view gauge system, thickness in mm, thickness in inches, and tolerance range
MS / CR Steel uses the US Standard Gauge (USG) system. Higher gauge number = thinner sheet. Standard: IS 513 (CR Sheet), IS 2062 (HR Sheet). Common range: Gauge 8 to Gauge 30.
| Gauge (USG) | Thickness (mm) | Thickness (inch) | Approx. Fraction | IS 513 Tolerance (mm) | Common Use in India |
|---|---|---|---|---|---|
| 3 | 6.073 | 0.2391" | 15/64" | ±0.30 | Heavy plate – structural |
| 4 | 5.695 | 0.2242" | 7/32" | ±0.30 | Heavy structural plate |
| 5 | 5.314 | 0.2092" | 13/64" | ±0.25 | Machine guards, thick panels |
| 6 | 4.935 | 0.1943" | 3/16" | ±0.25 | Structural members |
| 7 | 4.554 | 0.1793" | 11/64" | ±0.25 | Fabrication plate |
| 8 | 4.176 | 0.1644" | 5/32" | ±0.20 | Structural frame, brackets |
| 9 | 3.797 | 0.1495" | 9/64" | ±0.20 | Heavy sheet metal work |
| 10 | 3.416 | 0.1345" | 9/64" | ±0.20 | Machine frames, conveyors |
| 11 | 3.038 | 0.1196" | 1/8" | ±0.15 | Heavy enclosures, baseplates |
| 12 | 2.657 | 0.1046" | 7/64" | ±0.15 | Structural fabrication |
| 13 | 2.278 | 0.0897" | 3/32" | ±0.12 | Panels, enclosure panels |
| 14 | 1.897 | 0.0747" | 5/64" | ±0.10 | Trolleys, general fabrication |
| 15 | 1.709 | 0.0673" | 1/16" | ±0.10 | Automotive body panels |
| 16 | 1.519 | 0.0598" | 1/16" | ±0.08 | General MS sheet, doors |
| 17 | 1.367 | 0.0538" | 1/16" | ±0.08 | Enclosures, lockers |
| 18 | 1.214 | 0.0478" | 3/64" | ±0.06 | Most stocked CR sheet in India |
| 19 | 1.062 | 0.0418" | 3/64" | ±0.06 | Panels, light enclosures |
| 20 | 0.912 | 0.0359" | 1/32" | ±0.05 | Thin CR sheet, light panels |
| 21 | 0.836 | 0.0329" | 1/32" | ±0.05 | Light fabrication |
| 22 | 0.759 | 0.0299" | 1/32" | ±0.04 | Auto panels, light boxes |
| 23 | 0.683 | 0.0269" | 1/32" | ±0.04 | Thin panels |
| 24 | 0.607 | 0.0239" | 1/32" | ±0.04 | Light sheet metal, ventilation |
| 25 | 0.531 | 0.0209" | 1/64" | ±0.04 | Ventilation ducting |
| 26 | 0.455 | 0.0179" | 1/64" | ±0.03 | Very thin sheet, gaskets |
| 27 | 0.417 | 0.0164" | 1/64" | ±0.03 | Very thin applications |
| 28 | 0.378 | 0.0149" | 1/64" | ±0.03 | Ultra-thin sheet |
| 29 | 0.343 | 0.0135" | 1/64" | ±0.03 | Ultra-thin |
| 30 | 0.305 | 0.0120" | 1/80" | ±0.03 | Foil-like applications |
* Gauge 18 (1.214 mm) and Gauge 16 (1.519 mm) are the most widely stocked CR sheet sizes in India. IS 513 CR Sheet tolerances: ±0.04–0.10 mm for thickness up to 3.15 mm. Higher gauge = thinner sheet.
GI / Galvanized Sheet uses the US Standard Gauge (USG) system but GI gauges are slightly thicker than MS at the same gauge number — the zinc coating (Z275 = ~0.038 mm total both sides) adds to base metal thickness. Standard: IS 277:2018.
| Gauge (USG) | GI Thickness (mm) | Base Metal (mm) | Thickness (inch) | Z275 Zinc Coating | Common Use in India |
|---|---|---|---|---|---|
| 8 | 4.269 | ~4.23 | 0.1681" | 0.038 mm | Heavy structural GI |
| 10 | 3.510 | ~3.47 | 0.1382" | 0.038 mm | Heavy cladding |
| 11 | 3.132 | ~3.09 | 0.1233" | 0.038 mm | Heavy duty panels |
| 12 | 2.753 | ~2.71 | 0.1084" | 0.038 mm | Structural cladding |
| 13 | 2.372 | ~2.33 | 0.0934" | 0.038 mm | Industrial cladding |
| 14 | 1.994 | ~1.95 | 0.0785" | 0.038 mm | Heavy roofing, cladding India |
| 15 | 1.803 | ~1.76 | 0.0710" | 0.038 mm | Roofing, heavy panels |
| 16 | 1.613 | ~1.57 | 0.0635" | 0.038 mm | Standard roofing grade India |
| 17 | 1.461 | ~1.42 | 0.0575" | 0.038 mm | Roofing, purlins |
| 18 | 1.311 | ~1.27 | 0.0516" | 0.038 mm | Most stocked GI sheet in India |
| 19 | 1.158 | ~1.12 | 0.0456" | 0.038 mm | Light roofing, bus body |
| 20 | 1.006 | ~0.97 | 0.0396" | 0.038 mm | Light panels, HVAC |
| 21 | 0.930 | ~0.89 | 0.0366" | 0.038 mm | Light cladding |
| 22 | 0.853 | ~0.81 | 0.0336" | 0.038 mm | Light applications, bus body |
| 23 | 0.775 | ~0.74 | 0.0305" | 0.038 mm | Thin cladding |
| 24 | 0.701 | ~0.66 | 0.0276" | 0.038 mm | Light roofing, PPGI substrate |
| 25 | 0.625 | ~0.59 | 0.0246" | 0.038 mm | Light ventilation panels |
| 26 | 0.551 | ~0.51 | 0.0217" | 0.038 mm | Light sheet, decking |
| 28 | 0.472 | ~0.43 | 0.0186" | 0.038 mm | Very thin GI sheet |
| 30 | 0.396 | ~0.36 | 0.0156" | 0.038 mm | Ultra-thin GI foil |
* GI sheet is always slightly thicker than MS at the same gauge number due to the zinc coating. Z275 coating adds ~0.038 mm total (both sides). Gauge 16 (1.613 mm) and Gauge 18 (1.311 mm) GI are the most stocked roofing grades in India. Standard: IS 277:2018 (BIS).
Stainless Steel uses the US Standard Gauge (USG) system but SS gauge thicknesses are different from carbon steel at the same gauge number. Standard: IS 6528, AISI 304/316. Common range: Gauge 7 to Gauge 30.
| Gauge (USG) | SS Thickness (mm) | Thickness (inch) | MS Equivalent (mm) | Difference vs MS | Common Use in India |
|---|---|---|---|---|---|
| 7 | 4.554 | 0.1793" | 4.554 | 0.000 | Heavy structural SS |
| 8 | 4.191 | 0.1650" | 4.176 | +0.015 | Heavy SS fabrication |
| 9 | 3.759 | 0.1480" | 3.797 | -0.038 | Heavy SS panels |
| 10 | 3.404 | 0.1340" | 3.416 | -0.012 | Structural SS |
| 11 | 3.048 | 0.1200" | 3.038 | +0.010 | SS equipment panels |
| 12 | 2.769 | 0.1090" | 2.657 | +0.112 | SS frames, vessels |
| 13 | 2.413 | 0.0950" | 2.278 | +0.135 | Pharma, food equipment |
| 14 | 1.994 | 0.0785" | 1.897 | +0.097 | Standard SS sheet India |
| 15 | 1.753 | 0.0690" | 1.709 | +0.044 | SS cladding, panels |
| 16 | 1.588 | 0.0625" | 1.519 | +0.069 | Kitchen equipment |
| 17 | 1.422 | 0.0560" | 1.367 | +0.055 | SS panels, handrails |
| 18 | 1.270 | 0.0500" | 1.214 | +0.056 | Most stocked SS sheet India |
| 19 | 1.067 | 0.0420" | 1.062 | +0.005 | SS enclosures |
| 20 | 0.953 | 0.0375" | 0.912 | +0.041 | Light SS fabrication |
| 21 | 0.873 | 0.0344" | 0.836 | +0.037 | SS panels |
| 22 | 0.794 | 0.0313" | 0.759 | +0.035 | Thin SS sheet |
| 23 | 0.714 | 0.0281" | 0.683 | +0.031 | SS cladding, balustrades |
| 24 | 0.635 | 0.0250" | 0.607 | +0.028 | SS decorative panels |
| 25 | 0.559 | 0.0220" | 0.531 | +0.028 | Thin SS sheet |
| 26 | 0.476 | 0.0188" | 0.455 | +0.021 | Ultra-thin SS |
| 28 | 0.356 | 0.0140" | 0.378 | -0.022 | Thin SS applications |
| 30 | 0.305 | 0.0120" | 0.305 | 0.000 | Very thin SS |
* SS Gauge 18 (1.270 mm) and Gauge 16 (1.588 mm) are the most commonly stocked stainless steel sheet thicknesses in India. Note: SS is thicker than MS at the same gauge number in most cases. Never use the MS gauge chart for SS procurement — always verify from the SS-specific table.
Aluminium uses the Brown & Sharp (B&S) gauge system — completely different from USG steel. The same gauge number gives a different (thinner) thickness than MS or SS. Common alloys: 1100, 3003, 5052, 6061. Standard: IS 737.
| Gauge (B&S) | Al Thickness (mm) | Thickness (inch) | MS Gauge 18 Equiv.? | IS 737 Tolerance | Common Use in India |
|---|---|---|---|---|---|
| 1 | 7.348 | 0.2893" | — | ±0.30 | Heavy Al plate |
| 2 | 6.543 | 0.2576" | — | ±0.25 | Marine plate, structural |
| 3 | 5.827 | 0.2294" | — | ±0.25 | Structural Al fabrication |
| 4 | 5.189 | 0.2043" | — | ±0.20 | Heavy Al panels |
| 5 | 4.620 | 0.1819" | — | ±0.20 | Structural, tooling plate |
| 6 | 4.115 | 0.1620" | — | ±0.15 | Al frames, marine |
| 7 | 3.665 | 0.1443" | — | ±0.15 | Structural Al sheet |
| 8 | 3.264 | 0.1285" | — | ±0.12 | Heavy Al panels, enclosures |
| 9 | 2.906 | 0.1144" | — | ±0.12 | Al fabrication |
| 10 | 2.588 | 0.1019" | — | ±0.10 | Al frames, caravan panels |
| 11 | 2.304 | 0.0907" | — | ±0.10 | Al panels |
| 12 | 2.052 | 0.0808" | — | ±0.08 | Light Al structural |
| 13 | 1.829 | 0.0720" | — | ±0.08 | Al cladding |
| 14 | 1.628 | 0.0641" | — | ±0.07 | Al roofing, cladding India |
| 15 | 1.450 | 0.0571" | — | ±0.06 | Al panels, solar frames |
| 16 | 1.290 | 0.0508" | — | ±0.06 | Most stocked Al sheet India |
| 17 | 1.150 | 0.0453" | — | ±0.05 | Al enclosures, panels |
| 18 | 1.024 | 0.0403" | ≈ MS Gauge 20 | ±0.05 | Light Al sheet |
| 19 | 0.912 | 0.0359" | ≈ MS Gauge 20 | ±0.05 | Al body panels |
| 20 | 0.812 | 0.0320" | — | ±0.04 | Thin Al sheet |
| 22 | 0.644 | 0.0253" | — | ±0.04 | Very thin Al |
| 24 | 0.511 | 0.0201" | — | ±0.03 | Ultra-thin Al sheet |
| 26 | 0.405 | 0.0159" | — | ±0.03 | Al foil-like applications |
| 28 | 0.321 | 0.0126" | — | ±0.03 | Very thin Al |
| 30 | 0.254 | 0.0100" | — | ±0.02 | Al shim stock |
* Aluminium B&S Gauge 16 (1.290 mm) is the most widely stocked sheet thickness in India from Hindalco, Nalco, and importer stockists. Important: Al Gauge 18 B&S = 1.024 mm — very different from MS Gauge 18 USG = 1.214 mm. Never cross-use gauge tables between steel and aluminium.
Copper and Brass both use the Brown & Sharp (B&S) gauge system — same gauge numbers as Aluminium B&S. Thickness values are identical to Al B&S gauge. Common grades: ETP Copper (C11000), Brass CW508L (65:35).
| Gauge (B&S) | Cu / Brass (mm) | Thickness (inch) | Copper Area (cm²/m) | Common Copper Use | Common Brass Use |
|---|---|---|---|---|---|
| 4 | 5.189 | 0.2043" | 51.89 | Heavy bus bar plate | Heavy brass plate |
| 6 | 4.115 | 0.1620" | 41.15 | Bus bar, heat exchangers | Heavy brass sheet |
| 8 | 3.264 | 0.1285" | 32.64 | Roofing copper sheet | Decorative brass sheet |
| 10 | 2.588 | 0.1019" | 25.88 | Earthing strip, bus bar | Thick brass strip |
| 12 | 2.052 | 0.0808" | 20.52 | Bus bar, electrical sheet | Instrument panels |
| 14 | 1.628 | 0.0641" | 16.28 | General copper sheet | Brass sheet, nameplate |
| 16 | 1.290 | 0.0508" | 12.90 | Roofing, flashing | Most stocked brass sheet |
| 18 | 1.024 | 0.0403" | 10.24 | Light copper sheet | Brass decorative |
| 20 | 0.812 | 0.0320" | 8.12 | Thin copper sheet | Thin brass strip |
| 22 | 0.644 | 0.0253" | 6.44 | Very thin copper | Thin brass sheet |
| 24 | 0.511 | 0.0201" | 5.11 | Copper shim | Brass shim stock |
| 26 | 0.405 | 0.0159" | 4.05 | Copper foil | Thin brass strip |
| 28 | 0.321 | 0.0126" | 3.21 | Ultra-thin copper | Precision brass strip |
| 30 | 0.254 | 0.0100" | 2.54 | Copper foil / shim | Brass foil |
* Copper and Brass use identical B&S gauge thickness values. Copper B&S Gauge 16 (1.290 mm) is widely used for electrical bus bars and roofing copper in India. Brass B&S Gauge 16 (1.290 mm) is the most stocked decorative brass sheet. Source: B&S (Brown & Sharp) gauge standard.
All metals side-by-side — same gauge number, different thicknesses across gauge systems (USG for steel, B&S for non-ferrous). Use this to understand why Gauge 18 in MS ≠ Gauge 18 in Aluminium.
| Gauge | MS Steel USG (mm) |
GI Sheet USG (mm) |
SS Sheet USG (mm) |
Aluminium B&S (mm) |
Copper B&S (mm) |
Brass B&S (mm) |
|---|---|---|---|---|---|---|
| 8 | 4.176 | 4.269 | 4.191 | 3.264 | 3.264 | 3.264 |
| 10 | 3.416 | 3.510 | 3.404 | 2.588 | 2.588 | 2.588 |
| 11 | 3.038 | 3.132 | 3.048 | 2.304 | 2.304 | 2.304 |
| 12 | 2.657 | 2.753 | 2.769 | 2.052 | 2.052 | 2.052 |
| 13 | 2.278 | 2.372 | 2.413 | 1.829 | 1.829 | 1.829 |
| 14 | 1.897 | 1.994 | 1.994 | 1.628 | 1.628 | 1.628 |
| 15 | 1.709 | 1.803 | 1.753 | 1.450 | 1.450 | 1.450 |
| 16 | 1.519 | 1.613 | 1.588 | 1.290 | 1.290 | 1.290 |
| 17 | 1.367 | 1.461 | 1.422 | 1.150 | 1.150 | 1.150 |
| 18 | 1.214 | 1.311 | 1.270 | 1.024 | 1.024 | 1.024 |
| 19 | 1.062 | 1.158 | 1.067 | 0.912 | 0.912 | 0.912 |
| 20 | 0.912 | 1.006 | 0.953 | 0.812 | 0.812 | 0.812 |
| 21 | 0.836 | 0.930 | 0.873 | 0.723 | 0.723 | 0.723 |
| 22 | 0.759 | 0.853 | 0.794 | 0.644 | 0.644 | 0.644 |
| 24 | 0.607 | 0.701 | 0.635 | 0.511 | 0.511 | 0.511 |
| 26 | 0.455 | 0.551 | 0.476 | 0.405 | 0.405 | 0.405 |
| 28 | 0.378 | 0.472 | 0.356 | 0.321 | 0.321 | 0.321 |
| 30 | 0.305 | 0.396 | 0.305 | 0.254 | 0.254 | 0.254 |
* Highlighted rows (Gauge 14 and 18) are the most commonly referenced gauges in Indian fabrication. Key insight: Gauge 18 MS = 1.214 mm but Gauge 18 Aluminium (B&S) = 1.024 mm — a 0.190 mm difference. GI is always thicker than MS at the same gauge due to zinc coating. Never use the MS chart for aluminium, copper, or brass procurement.
The two main gauge standards used for sheet metal in India and the metals each applies to
Important rules for correctly converting gauge numbers to mm in India — common mistakes and how to avoid them