India's most complete GI sheet gauge reference updated for 2026. Find galvanized steel gauge thickness in mm, inches, and weight per m² — as per IS 277:2018 standard with latest zinc coating grades Z120 to Z600.
Standard galvanized steel (GI sheet) gauge chart from Gauge 8 to Gauge 30 — thickness in inches, mm, and weight per square metre as per IS 277:2018 – Bureau of Indian Standards (BIS). Updated January 2026.
| Gauge No. | Thickness (Inches) | Thickness (mm) | Weight (kg/m²) | Common Use in India 2026 |
|---|---|---|---|---|
| 8 | 0.1681 | 4.270 | 33.52 | Heavy structural panels, blast walls |
| 9 | 0.1532 | 3.891 | 30.54 | Industrial frames & heavy enclosures |
| 10 | 0.1382 | 3.510 | 27.55 | Heavy roofing, machinery guards |
| 11 | 0.1233 | 3.132 | 24.59 | Structural fabrication, load-bearing frames |
| 12 | 0.1084 | 2.753 | 21.61 | Storage tanks, silo bin walls |
| 13 | 0.0934 | 2.372 | 18.62 | Auto body panels, bus body fabrication |
| 14 | 0.0785 | 1.994 | 15.65 | Industrial roofing, HVAC ducts |
| 15 | 0.0710 | 1.803 | 14.15 | Light ducts, partitions, cold storage panels |
| 16 | 0.0635 | 1.613 | 12.66 | Agriculture equipment, grain storage bins |
| 17 | 0.0575 | 1.461 | 11.47 | Ventilation systems, light frames |
| 18 | 0.0516 | 1.310 | 10.28 | GI plain sheets, cable trays, false ceilings |
| 19 | 0.0456 | 1.158 | 9.09 | Light construction, fencing, cladding |
| 20 | 0.0396 | 1.006 | 7.90 | Electrical enclosures, switchgear panels |
| 21 | 0.0366 | 0.930 | 7.30 | Light panels, ceiling trims |
| 22 | 0.0336 | 0.853 | 6.70 | Corrugated roofing sheets (most common in India) |
| 23 | 0.0306 | 0.777 | 6.10 | Light roofing, canopies, lean-tos |
| 24 | 0.0276 | 0.701 | 5.50 | Thin enclosures, appliance liners |
| 25 | 0.0247 | 0.627 | 4.92 | Decorative panels, signage backing |
| 26 | 0.0217 | 0.551 | 4.33 | GI wire mesh backing |
| 27 | 0.0202 | 0.513 | 4.03 | Thin liners, flashing strips |
| 28 | 0.0187 | 0.475 | 3.73 | Packing covers, light cans |
| 29 | 0.0172 | 0.437 | 3.43 | Very light applications |
| 30 | 0.0157 | 0.399 | 3.13 | Foil covers, gasket liners |
* Highlighted rows (Gauge 10, 14, 16, 18, 22) are most commonly stocked by Indian GI sheet suppliers in 2026. Weight values calculated at galvanized steel density ~7,850 kg/m³ including standard Z275 zinc coating. Reference: IS 277:2018 – Bureau of Indian Standards (BIS). For MS sheet gauge data, see our MS Sheet Weight Chart – India.
Follow these 6 steps to correctly identify the right galvanized steel gauge for your Indian construction or fabrication project in 2026
Gauge numbers are inverse — a higher gauge number means thinner steel. Gauge 8 is the thickest (4.270 mm) and Gauge 30 is the thinnest (0.399 mm) in this 2026 table.
Indian suppliers quote GI sheets in mm. Locate your required thickness in the mm column and cross-check with the gauge number to confirm the specification before ordering.
The kg/m² column lets you estimate total material weight. Multiply by the total sheet area (length × width in metres) to get weight for procurement and logistics planning.
In India, GI sheets are sold with zinc coating grades Z120 to Z600 as per IS 277:2018. Always confirm the coating grade with your supplier — Z275 for standard roofing, Z450/Z600 for coastal areas.
If your drawing uses inches (common in older IS or imported specs), use the inches column directly. Quick conversion formula: 1 inch = 25.4 mm.
Roofing → Gauge 14–18. Electrical panels → Gauge 18–20. Corrugated roofing → Gauge 22–24. Coastal applications → add minimum Z350 coating. Refer to the applications section below for full details.
How to calculate the total weight of galvanized steel sheets from gauge dimensions and zinc coating grade
Thickness = 1.310 mm
Weight = 2.44 × 1.22 × 1.310 × 7.85
= ≈ 30.56 kg per sheet
Most Indian GI sheets are available in 8×4 ft (2.44 × 1.22 m) and 10×3 ft (3.048 × 0.914 m). Some suppliers also offer 6×3 ft sheets. Corrugated GC sheets are typically 8×2.5 ft in southern India.
Multiply the kg/m² value from the table by the sheet area. For a Gauge 18 sheet (10.28 kg/m²) at 2.977 m²: 10.28 × 2.977 = ≈ 30.60 kg — same result, faster calculation without separate formula.
Z275 coating adds approx. 0.275 kg/m². Z450 adds 0.45 kg/m². Z600 adds 0.60 kg/m². The kg/m² values in this 2026 table already include standard Z275 coating weight per IS 277:2018.
Why galvanized steel gauge thickness is slightly higher than plain mild steel at the same gauge number — and why you must use the correct table
| Gauge No. | Galvanized Steel mm (2026) | Mild Steel / CR Sheet mm | Difference (mm) | Reason |
|---|---|---|---|---|
| 14 | 1.994 | 1.897 | +0.097 | Zinc hot-dip coating adds ~0.10 mm |
| 16 | 1.613 | 1.519 | +0.094 | Zinc hot-dip coating adds ~0.10 mm |
| 18 | 1.310 | 1.214 | +0.096 | Zinc hot-dip coating adds ~0.10 mm |
| 20 | 1.006 | 0.912 | +0.094 | Zinc hot-dip coating adds ~0.10 mm |
| 22 | 0.853 | 0.759 | +0.094 | Zinc hot-dip coating adds ~0.10 mm |
| 24 | 0.701 | 0.607 | +0.094 | Zinc hot-dip coating adds ~0.10 mm |
The zinc coating (hot-dip galvanizing) adds ~0.09–0.10 mm total thickness. Always use the galvanized gauge table — not the MS gauge table — when working with GI sheets. Using MS thickness will underestimate weight by 5–8%. For MS sheet thickness reference, see our Gauge to mm Conversion Chart.
Standard zinc coating designations Z120 to Z600 for galvanized steel sheets as per IS 277:2018 — used across all Indian steel markets in 2026
Z275 is the default coating grade stocked by most Indian dealers in 2026. For coastal cities (Mumbai, Chennai, Vishakhapatnam, Goa), Z350 or Z450 is recommended. For marine/industrial: Z600. Source: Bureau of Indian Standards – IS 277:2018. See also: Tata Steel GI Sheets and JSW Galvanized Steel Products.
Major industries and uses of GI sheets across India by gauge thickness range — updated for 2026
Gauge 14–18 GI sheets are widely used for industrial sheds, warehouses, and roofing in rural and semi-urban India. Corrugated Gauge 22 sheets remain the most common for residential roofing in 2026.
Gauge 18–20 GI sheets are the standard for electrical panels, distribution boards, cable trays, and switchgear enclosures across India per IS standards — and remain the top choice in 2026.
Gauge 14–18 is used for HVAC air ducts, ventilation systems, and exhaust channels. Thicker Gauge 14–16 for high-pressure industrial HVAC; Gauge 18 for commercial AC ducting systems.
Gauge 16–18 GI sheets are used for grain storage bins, silos, and water tanks across agricultural India, especially in Punjab, Haryana, MP, and UP — critical to food security infrastructure in 2026.
Gauge 18–22 GI sheets are used for automobile body panels, car underbodies, and bus/EV body fabrication — a major and growing application in India's expanding electric vehicle sector in 2026.
Thin Gauge 24–28 GI sheets are used for tin containers, metal packaging, and light covers in the FMCG, pharmaceutical, and food processing industries across India.
Best practices when sourcing IS 277:2018 compliant galvanized steel sheets from Indian suppliers and dealers in 2026
Ask your steel supplier for the IS 277:2018 test certificate. It confirms zinc coating weight, base metal grade (D or DD), and dimensional tolerance compliance. Major brands like TATA BlueScope and JSW Steel provide this for every coil/sheet batch.
In India, GI sheets are often sold by weight (per kg). Cross-check using: Total weight = Number of sheets × Sheet area (m²) × kg/m² from this 2026 gauge table. A discrepancy of more than 2% should be queried with the supplier before accepting delivery.
For coastal areas (Tamil Nadu, Kerala, Goa, Odisha, AP coast), always use minimum Z350 or Z450 coating. Inland dry regions (Rajasthan, UP, MP, Delhi NCR) can use Z275 for most roofing. For marine/chemical plants — use Z600. See GI Sheet Coating Guide.
Tolerance as per IS 277:2018 is ±0.05 mm for sheets up to 1.6 mm and ±0.08 mm for thicker sheets. Always check with a calibrated micrometer at delivery — under-gauge sheets are commonly sold in unorganised Indian markets in 2026.
For structural and roofing applications, only buy from ISI-marked manufacturers. Top reliable brands in India 2026: TATA BlueScope, JSW Steel, SAIL, and Bhushan Power & Steel — all IS 277:2018 compliant.
Always add 8% to your calculated sheet quantity for cutting wastage, overlaps, and defective sheets. For roofing with ridge and eave overlaps, a 10% addition is standard practice in Indian construction projects in 2026.
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Common questions about GI sheet gauge, thickness, weight, IS 277 zinc coating grades, and buying tips answered for India 2026