How thick is 13 gauge galvanised steel?

13 gauge galvanised steel is 0.0934 in thick, which is 2.373 mm. A square foot weighs 3.75 lb (18.31 kg/m²).

What is 13 gauge galvanised steel in mm?

2.373 mm. The gauge number is an index into the galvanized-MSG system rather than a measurement, so it converts to a fixed thickness rather than a round metric figure.

Is 13 gauge galvanised steel thicker than 12 gauge?

No — a lower gauge number is thicker sheet. 12 gauge galvanized is 0.1084 in (2.752 mm) against 0.0934 in (2.373 mm) for 13 gauge galvanised steel, a difference of 0.0150 in.

Why is 13 gauge a different thickness in other materials?

Because each material is indexed on its own gauge system. At 13 gauge: Aluminium 0.0720 in (B&S), Galvanized 0.0934 in (galvanized-MSG), Steel 0.0897 in (MSG), US Standard 0.0938 in (USG). The number is a position in a series, not a thickness, so 3 other readings of "13 gauge" are all equally correct.

Sheet metal · Galvanized Steel · galvanized-MSG

13 Gauge Galvanised Steel Thickness in Inches and Millimetres

https://shopmath.org/gauges/galvanized/13 · data verified August 1, 2026

13 gauge galvanised steel sheet is 0.0934 in thick — 2.373 mm. A square foot weighs 3.75 lb (18.31 kg/m²). The gauge number indexes the galvanized-MSG system, so the same number is a different thickness in another material — the comparison is below. Thicknesses are nominal, before mill tolerance.

Gauge: 13 ga
Material: Galvanized Steel
Inch: 0.0934
mm: 2.373
System: galvanized-MSG

13 Gauge Galvanised Steel · nominal thickness

0.0934 in

Millimetre: 2.373mm
Weight: 3.75lb/ft²
Weight: 18.31kg/m²

Nominal thickness on the galvanized-MSG system. Gauge numbers are material-specific — "13 gauge" on its own does not name a thickness.

13 Gauge Galvanised Steel Sheet Thickness

13 Gauge Galvanised Steel is defined by the MSG plus zinc coating allowance, not by a measurement — the gauge number is an index into that system, which is why the same number means a different thickness in another material.

13 Gauge Galvanised Steel — thickness and weight
Property	Value
Thickness, decimal inch	0.0934 in
Thickness, millimetre	2.373 mm
Weight per square foot	3.75 lb/ft²
Weight per square metre	18.31 kg/m²
Gauge system	galvanized-MSG

Nominal thickness. Mill tolerance on sheet is typically a few thousandths of an inch either way and varies with width and process; measure the stock when the fit matters.

13 Gauge Thickness in Every Other Sheet Material

Gauge 13 spans 0.0720 in to 0.0938 in depending on the material, because each material is indexed on a different gauge system. Ordering sheet by gauge without naming the material is how the wrong thickness arrives.

Thickness of 13 gauge sheet across materials
Property	Property	Thickness
Material	Gauge system	in	mm
Sheet Aluminium	B&S	0.0720	1.828
Galvanized Steel	galvanized-MSG	0.0934	2.373
Sheet Steel	MSG	0.0897	2.278
U.S. Standard Gauge	USG	0.0938	2.381

Steel uses the Manufacturers' Standard Gauge, galvanised adds a zinc-coating allowance to the steel thickness, aluminium and other non-ferrous sheet use the Brown & Sharpe geometric series, and U.S. Standard is the 1893 statute on a wrought-iron basis.

Gauges Either Side of 13 Gauge Galvanised Steel

A higher gauge number is thinner sheet. The steps are not equal — the gauge systems are geometric, so the difference between two gauges shrinks as the sheet gets thinner.

Galvanized Steel gauges adjacent to 13 gauge
Property	Thickness
Gauge	in	mm
11 ga	0.1233	3.132
12 ga	0.1084	2.752
13 ga	0.0934	2.373
14 ga	0.0785	1.993
15 ga	0.0710	1.803

Sources and Method for 13 Gauge Galvanised Steel Thickness

13 Gauge Galvanised Steel thicknesscomputed

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

Verified against Wikipedia Sheet metal, Standard sheet metal gauges table (CC BY-SA 4.0) — 137/137 checks passed at 0.05 mil

Computed from the standard's formulas, then checked against published tables.

Formula

Weight per square foot, sheet steel

lb/ft²  =  thickness (in) × 41.82

  0.0934 × 41.82  =  3.75 lb/ft²

41.82 lb/ft² per inch of thickness is the Manufacturers' Standard Gauge basis for steel. The U.S. Standard Gauge of 1893 uses a wrought-iron basis of 40 lb/ft² per inch, which is why the two systems differ.

Assumptions

Thicknesses are nominal. Mill tolerance varies with width, process and material and is not part of the gauge definition.
Gauge is an index into a material-specific system, not a unit. A gauge number without a material is ambiguous by construction.
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

How this data is built and checked →

How to Cite This 13 Gauge Galvanised Steel Reference

Citation

ShopMath. "13 Gauge Galvanised Steel Thickness in Inches and Millimetres." ShopMath, verified August 1, 2026, https://shopmath.org/gauges/galvanized/13

BibTeX

@misc{shopmath-gauges-galvanized-13,
  title        = {13 Gauge Galvanised Steel Thickness in Inches and Millimetres},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/gauges/galvanized/13}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/gauges/galvanized/13

Common Questions About 13 Gauge Galvanised Steel

How thick is 13 gauge galvanised steel?: 13 gauge galvanised steel is 0.0934 in thick, which is 2.373 mm. A square foot weighs 3.75 lb (18.31 kg/m²).
What is 13 gauge galvanised steel in mm?: 2.373 mm. The gauge number is an index into the galvanized-MSG system rather than a measurement, so it converts to a fixed thickness rather than a round metric figure.
Is 13 gauge galvanised steel thicker than 12 gauge?: No — a lower gauge number is thicker sheet. 12 gauge galvanized is 0.1084 in (2.752 mm) against 0.0934 in (2.373 mm) for 13 gauge galvanised steel, a difference of 0.0150 in.
Why is 13 gauge a different thickness in other materials?: Because each material is indexed on its own gauge system. At 13 gauge: Aluminium 0.0720 in (B&S), Galvanized 0.0934 in (galvanized-MSG), Steel 0.0897 in (MSG), US Standard 0.0938 in (USG). The number is a position in a series, not a thickness, so 3 other readings of "13 gauge" are all equally correct.

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