---
type: "sheet-metal-gauge"
gauge_number: "31"
material: "galvanized"
material_name: "Galvanized Steel"
gauge_system: "galvanized-MSG"
thickness_in: 0.0142
thickness_mm: 0.3606
weight_lb_per_sqft: 0.4375
weight_kg_per_sqm: 2.136
standard: "15 U.S.C. 206; Manufacturers' Standard Gauge; Brown & Sharpe / AWG"
verified: "August 1, 2026"
url: https://shopmath.org/gauges/galvanized/31
---

# 31 Gauge Galvanized Steel — Sheet Metal Thickness in Inches and Millimetres

31 gauge galvanized is 0.0142 in (0.361 mm) thick. That figure is on the galvanized-MSG — gauge is a material-specific numbering scheme, not a unit, so the same number is a different thickness in another material.

- **Gauge**: 31
- **Material**: Galvanized Steel
- **Gauge system**: galvanized-MSG
- **Thickness**: 0.0142 in (0.361 mm)
- **Weight**: 0.438 lb/ft² (2.14 kg/m²)

## 31 Gauge Galvanized Steel Thickness

| Property | Value |
| --- | --- |
| Thickness (in) | 0.0142 |
| Thickness (mm) | 0.361 |
| Weight (lb/ft²) | 0.438 |
| Weight (kg/m²) | 2.14 |
| Gauge system | galvanized-MSG |

## 31 Gauge Across Materials

The same gauge number in every material this reference covers. They differ because each material carries its own gauge system, not because one chart is wrong.

| Material | Gauge system | Thickness (in) | Thickness (mm) | lb/ft² | kg/m² |
| --- | --- | --- | --- | --- | --- |
| [Sheet Aluminium](https://shopmath.org/gauges/aluminum/31.md) | B&S | 0.0089 | 0.227 |  |  |
| Galvanized Steel (this page) | galvanized-MSG | 0.0142 | 0.361 | 0.438 | 2.14 |
| [Sheet Steel](https://shopmath.org/gauges/steel/31.md) | MSG | 0.0105 | 0.266 | 0.438 | 2.14 |
| [U.S. Standard Gauge](https://shopmath.org/gauges/us-standard/31.md) | USG | 0.0109 | 0.278 | 0.438 | 2.14 |

## Sources and Method for 31 Gauge Galvanized Steel

### Galvanized Steel gauge thicknesses

- **Source**: 15 U.S.C. 206 (Act of Mar. 3, 1893, ch. 221, 27 Stat. 746) — U.S. Standard Gauge for sheet and plate iron and steel; 15 U.S.C. 206 statutory weights; MSG (41.82 lb/ft2 per inch), galvanized zinc allowance, and Brown & Sharpe formula per docs/research/data-sourcing.md §3.7
- **Method**: computed
- **Verified against**: Wikipedia Sheet metal, Standard sheet metal gauges table (CC BY-SA 4.0) — 137/137 checks passed at 0.05 mil

### Assumptions

- Gauge is a numbering scheme, not a unit. A thickness is only meaningful with its material and gauge system stated.
- Sheet is supplied to a mill tolerance around these nominal thicknesses; measure the stock when the fit matters.
- Dataset scope: EXCLUDED: stainless steel (genuinely ambiguous convention, only one source in hand), zinc, copper, brass, steel tube wall.

**Data last verified**: August 1, 2026

## Common Questions About 31 Gauge Galvanized Steel

### How thick is 31 gauge galvanized?

31 gauge galvanized is 0.0142 in (0.361 mm) thick, on the galvanized-MSG.

### What is 31 gauge in mm?

31 gauge galvanized is 0.361 mm. Gauge is not a unit — the same number means a different thickness in a different material, so the material has to be stated with it.

### Is 31 gauge the same thickness in every material?

No. 31 gauge is 0.0142 in in galvanized steel, but 0.0089 in in sheet aluminium, 0.0105 in in sheet steel, 0.0109 in in u.s. standard gauge. Each material uses its own gauge system: B&S; galvanized-MSG; MSG; USG.

### How much does 31 gauge galvanized weigh per square foot?

0.438 lb per square foot (2.14 kg per square metre).

## Related pages

- Thicker (lower gauge number): [30 gauge galvanized steel](https://shopmath.org/gauges/galvanized/30.md) — 0.0157 in
- Thinner (higher gauge number): [32 gauge galvanized steel](https://shopmath.org/gauges/galvanized/32.md) — 0.0135 in
- All galvanized steel gauges: [Galvanized Steel gauge chart](https://shopmath.org/gauges/galvanized.md)
- All materials and gauges: [Sheet metal gauge reference](https://shopmath.org/gauges.md)
- Full cross-material chart: [Sheet metal gauge chart](https://shopmath.org/charts/sheet-metal-gauge.md)

---

*Source: [ShopMath](https://shopmath.org/gauges/galvanized/31) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*