Gauge vs mm – Quick Reference Chart for Steel, GI, SS & Aluminium | SheetGauge

Gauge vs mm — Quick Reference Guide

Instantly convert any gauge to mm for MS, GI, stainless steel and aluminium sheets. Includes visual thickness comparison, multi-material table and a live gauge finder — India focused, 2026 updated.

Instant Lookup 4 Materials Visual Chart Mobile Friendly

Gauge vs mm Finder Tool

Type any gauge number and select material — get the exact thickness in mm and inches instantly

Gauge Number

Material

Gauge

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Material

—

Thickness

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Thickness

—

inches

Weight (kg/m²)

—

kg/m²

Gauge vs mm — Visual Thickness Scale

Bar length proportional to actual thickness — MS/GI standard gauges used in India

Gauge vs mm Chart — All Materials

Side-by-side gauge to mm comparison for MS, GI, Stainless Steel and Aluminium — standard values used in India

Gauge	MS / Mild Steel (mm)	GI Sheet (mm)	Stainless Steel (mm)	Aluminium (mm)	Category
8 G	4.176	4.267	4.191	3.264	Heavy plate
10 G	3.416	3.510	3.571	2.588	Heavy plate
12 G	2.657	2.753	2.778	2.052	Heavy sheet
14 G	1.897	1.994	1.984	1.628	Medium sheet
16 G	1.518	1.613	1.588	1.290	Medium sheet
18 G	1.214	1.311	1.270	1.024	Medium sheet
20 G	0.911	1.006	0.952	0.812	Light sheet
22 G	0.759	0.853	0.794	0.644	Light sheet
24 G	0.607	0.701	0.635	0.511	Light sheet
26 G	0.455	0.549	0.476	0.405	Thin sheet
28 G	0.378	0.396	0.396	0.321	Thin sheet
30 G	0.303	0.320	0.317	0.255	Thin sheet
32 G	0.274	0.274	0.254	0.202	Ultra-thin

* MS values per US Standard Gauge (ASTM); GI values include zinc coating per IS 277; SS values per ASTM A480; Aluminium per B&S Gauge. GI gauge is slightly thicker than MS due to zinc coating on both sides.

Gauge	Thickness (mm)	Thickness (inch)	Weight (kg/m²)	Common Use in India
8 G	4.176	0.1644	32.78	Heavy structural plates, floor plates
10 G	3.416	0.1345	26.82	Fabrication, pressure vessels
12 G	2.657	0.1046	20.86	Machine guards, industrial enclosures
14 G	1.897	0.0747	14.89	Hoppers, bins, structural panels
16 G	1.518	0.0598	11.92	Cabinets, covers, light fabrication
18 G	1.214	0.0478	9.53	Electrical panels, general fabrication
20 G	0.911	0.0359	7.15	Light enclosures, guards
22 G	0.759	0.0299	5.96	Thin panels, decorative cladding
24 G	0.607	0.0239	4.76	Light sheet metal work
26 G	0.455	0.0179	3.57	Thin sheet, insulation cladding

Gauge	Thickness (mm)	Base Steel (mm)	Weight Z275 (kg/m²)	Weight 8×4 ft (kg)	Common Use in India
10 G	3.000	2.86	23.82	70.76	Heavy fabrication, structural
12 G	2.500	2.36	19.90	59.10	Equipment enclosures
14 G	2.000	1.86	15.98	47.47	Heavy floors, platforms
16 G	1.600	1.46	12.84	38.14	Floor plates, stiffened panels
18 G	1.250	1.11	10.09	29.97	Tank covers, structural panels
20 G	1.000	0.86	8.13	24.14	Heavy roofing, storage sheds
22 G	0.800	0.66	6.56	19.48	Industrial roofing, side cladding
24 G	0.630	0.49	5.22	15.51	Commercial roofing
26 G	0.500	0.36	4.20	12.47	Residential roofing (most popular)
28 G	0.400	0.26	3.42	10.16	Light roofing, cladding
30 G	0.300	0.16	2.63	7.81	Interior lining, ducting
32 G	0.250	0.11	2.24	6.65	Light ceilings, partitions

Gauge	Thickness (mm)	Thickness (inch)	Weight SS 304 (kg/m²)	Weight SS 316 (kg/m²)	Common Use
8 G	4.191	0.1650	33.23	33.44	Heavy tanks, pressure parts
10 G	3.571	0.1406	28.32	28.50	Vessels, structural SS fabrication
12 G	2.778	0.1094	22.03	22.18	Food processing equipment
14 G	1.984	0.0781	15.73	15.84	Kitchen sinks, cladding
16 G	1.588	0.0625	12.59	12.67	Pharma equipment, liners
18 G	1.270	0.0500	10.07	10.14	General SS sheet fabrication
20 G	0.952	0.0375	7.55	7.60	Light panels, covers
22 G	0.794	0.0313	6.29	6.34	Decorative sheets
24 G	0.635	0.0250	5.03	5.07	Light cladding, trays
26 G	0.476	0.0188	3.77	3.80	Thin SS liners

Gauge (B&S)	Thickness (mm)	Thickness (inch)	Weight (kg/m²)	Common Use
8 G	3.264	0.1285	8.81	Structural aluminium plates
10 G	2.588	0.1019	6.99	Fabricated aluminium parts
12 G	2.052	0.0808	5.54	Aluminium chequered plates
14 G	1.628	0.0641	4.40	Panels, housings
16 G	1.290	0.0508	3.48	Aircraft-style panels, enclosures
18 G	1.024	0.0403	2.76	Light aluminium fabrication
20 G	0.812	0.0320	2.19	Thin panels, covers
22 G	0.644	0.0253	1.74	Lightweight cladding
24 G	0.511	0.0201	1.38	Foil-type sheet work
26 G	0.405	0.0159	1.09	Ultra-light covers

Why Gauge vs mm Matters — Explained

Understanding the gauge system before you order or fabricate sheet metal

Higher Gauge = Thinner

↑ G = ↓ mm

inverse relationship

32G (0.25mm) is thinner than 10G (3.0mm) — counterintuitive but universal

GI > MS at Same Gauge

+0.07–0.14mm

zinc adds thickness

GI 26G = 0.50mm total; MS 26G = 0.455mm base — zinc coating adds measurable thickness

No Single Standard

4+ Gauge Systems

SWG / BWG / B&S / US

Same gauge number means different mm in different standards. Always confirm with supplier

India Uses SWG

IS / SWG

most common in India

Indian steel suppliers typically follow SWG (Standard Wire Gauge) / IS standard for sheet thickness

Plate vs Sheet

> 6 mm = Plate

industry convention

Steel above ~6mm (below gauge 7) is classified as plate, not sheet, in most Indian standards

Always Verify in mm

mm on MTC

mill test certificate

For procurement and structural design, always specify thickness in mm — not gauge — on purchase orders

Where Gauge vs mm Reference Is Used

Industries and trades that rely on gauge-to-mm conversion daily in India

Steel Fabrication

Fabricators receive drawings in mm and purchase material in gauge. Quick gauge vs mm conversion avoids ordering the wrong thickness and costly material rejection at site.

Roofing & Cladding

GI roofing sheets in India are specified by gauge (26G, 24G, 22G). Contractors and builders need the mm equivalent to specify correctly in tenders and verify delivered material.

HVAC Duct Fabrication

Duct thickness is specified in gauge per SMACNA standards. HVAC contractors in India convert gauge to mm to select the correct GI coil from stockists and calculate duct weight.

Electrical Enclosures

IS 2147 specifies enclosure sheet thickness in mm. Electrical panel manufacturers use gauge reference charts to verify that incoming CR/GI sheets meet the specified mm thickness.

Process Equipment

Stainless steel tanks, hoppers, and vessels are designed in mm but often purchased in gauge. Engineers cross-reference SS gauge charts to confirm material selection against design drawings.

Procurement & Buying

Steel stockists in India list GI and CR sheets by gauge. Procurement teams need the gauge vs mm table to convert design drawings into correct purchase order specifications.

Pro Tips — Gauge vs mm for Indian Users

Common mistakes and best practices when working with sheet metal gauges in India

Never Assume One Standard for All

A 16G stainless steel sheet (1.588mm) and a 16G MS sheet (1.518mm) are not the same thickness. Always mention the material when specifying gauge — or better, just specify in mm on all documents.

Use mm on Purchase Orders

Specify thickness in mm (not gauge) on all purchase orders to avoid ambiguity between suppliers using different gauge standards. Write e.g. "2.00 mm thick MS HR sheet (approx 14G)" for clarity.

Verify Thickness on Delivery

Use a digital vernier calliper to spot-check sheet thickness on every delivery. Mill tolerance for MS sheets is typically ±0.1–0.2mm (±7.5% per IS 1730). Under-gauge material increases structural risk and inflates cost per kg.

GI Gauge Includes Coating

The GI sheet thickness in the gauge table includes the zinc coating on both sides. For structural calculations, use the base steel thickness (GI gauge mm minus ~0.14mm for Z275) when calculating section properties or weld joint design.

Calculate Weight Before Ordering

Once you confirm the gauge vs mm conversion, use our MS Sheet Weight Calculator or GI Sheet Weight Calculator to get total weight per sheet and per bundle for freight and costing purposes.

Quote Documents — Always State Both

In tender documents and quotations, write both gauge and mm (e.g. "26G / 0.50mm GI Sheet IS 277, Z275"). This prevents disputes between clients, consultants and fabricators who may reference different gauge systems.

Related Weight Calculators

After confirming your gauge vs mm — calculate exact weight with these tools

Frequently Asked Questions — Gauge vs mm

Common questions from fabricators, contractors and buyers in India

What gauge is 1mm in MS sheet?

1mm MS sheet is closest to 20 gauge (0.911mm) or falls between 19G (1.062mm) and 20G (0.911mm). In Indian market practice, 1.00mm MS CR/HR sheet is often loosely called "20G" but the nearest standard gauge is 19G at 1.062mm. For precision work, always specify 1.00mm on your purchase order rather than relying on gauge designation.

What is 26 gauge GI sheet thickness in mm?

26 gauge GI sheet is 0.50mm thick (total including zinc coating). The base steel is approximately 0.36mm and the Z275 zinc coating adds approximately 0.14mm on both sides combined. 26G is the most popular gauge for residential roofing in India — it offers a balance between strength and cost. Weight per 8×4 ft sheet is approximately 12.47 kg at Z275 coating.

Why is GI sheet thicker than MS sheet at the same gauge?

GI (galvanized iron) sheet thickness includes the zinc coating applied on both surfaces during the hot-dip galvanizing process. A Z275 coating adds approximately 0.07–0.14mm to the total sheet thickness compared to the bare MS base. This is why 26G GI = 0.50mm while the equivalent MS sheet base is around 0.36–0.455mm. When designing joints or calculating net metal section, use the base steel thickness (excluding coating) for structural calculations.

Which gauge system is used in India for steel sheets?

India primarily uses the SWG (Standard Wire Gauge) system, which aligns closely with the US Standard Gauge for sheet and plate. IS 1730 (for MS plates and sheets) specifies thicknesses in mm but Indian stockists and fabricators commonly refer to SWG gauge numbers in trade. For GI sheets, IS 277 specifies gauge numbers that map to specific mm thicknesses. Aluminium sheet in India often follows the B&S (Brown & Sharpe) gauge system.

What is the thickness of 16 gauge stainless steel in mm?

16 gauge stainless steel is 1.588mm thick (0.0625 inches) per ASTM A480 standard. This is slightly thicker than 16G MS (1.518mm) due to the different gauge standard used for stainless steel. In India, 16G SS 304 sheet weighs approximately 12.59 kg/m² (using SS 304 density of 7.93 g/cm³). It is commonly used for pharma equipment, commercial kitchen liners, and chemical process enclosures.

How do I convert gauge to mm without a chart?

There is no universal mathematical formula to convert gauge to mm because the gauge system is historical and not linear. You must use a reference table for your specific material and gauge standard. As a rough thumb rule for MS/GI sheets commonly used in India: Thickness (mm) ≈ (30 − Gauge) × 0.15 — this gives approximate values for 16G to 28G range but should not be used for precision work. Always use the chart above or confirm with your supplier's mill test certificate.