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Sheet metal · U.S. Standard Gauge · USG

7 Gauge U.S. Standard Thickness in Inches and Millimetres

https://shopmath.org/gauges/us-standard/7 · data verified August 1, 2026

7 gauge U.S. Standard sheet is 0.1875 in thick — 4.763 mm. A square foot weighs 7.50 lb (36.62 kg/m²). The gauge number indexes the USG system, so the same number is a different thickness in another material — the comparison is below. Thicknesses are nominal, before mill tolerance.

Gauge
7 ga
Material
U.S. Standard Gauge
Inch
0.1875
mm
4.763
System
USG

7 Gauge U.S. Standard · nominal thickness

0.1875 in

Millimetre
4.763mm
Weight
7.50lb/ft²
Weight
36.62kg/m²

Nominal thickness on the USG system. Gauge numbers are material-specific — "7 gauge" on its own does not name a thickness.

7 Gauge U.S. Standard Sheet Thickness

7 Gauge U.S. Standard is defined by the 15 U.S.C. 206 (wrought iron basis), 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.

7 Gauge U.S. Standard — thickness and weight
PropertyValue
Thickness, decimal inch0.1875 in
Thickness, millimetre4.763 mm
Weight per square foot7.50 lb/ft²
Weight per square metre36.62 kg/m²
Gauge systemUSG

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.

7 Gauge Thickness in Every Other Sheet Material

Gauge 7 spans 0.1443 in to 0.1875 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 7 gauge sheet across materials
PropertyPropertyThickness
MaterialGauge systeminmm
Sheet AluminiumB&S0.14433.665
Sheet SteelMSG0.17934.555
U.S. Standard GaugeUSG0.18754.763

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 7 Gauge U.S. Standard

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.

U.S. Standard Gauge gauges adjacent to 7 gauge
PropertyThickness
Gaugeinmm
5 ga0.21885.556
6 ga0.20315.159
7 ga0.18754.763
8 ga0.17194.366
9 ga0.15633.969

Sources and Method for 7 Gauge U.S. Standard Thickness

7 Gauge U.S. Standard 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

  0.1875 × 41.82  =  7.50 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 7 Gauge U.S. Standard Reference

Citation

ShopMath. "7 Gauge U.S. Standard Thickness in Inches and Millimetres." ShopMath, verified August 1, 2026, https://shopmath.org/gauges/us-standard/7

BibTeX

@misc{shopmath-gauges-us-standard-7,
  title        = {7 Gauge U.S. Standard Thickness in Inches and Millimetres},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/gauges/us-standard/7}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/gauges/us-standard/7

Common Questions About 7 Gauge U.S. Standard

How thick is 7 gauge U.S. Standard?

7 gauge U.S. Standard is 0.1875 in thick, which is 4.763 mm. A square foot weighs 7.50 lb (36.62 kg/m²).

What is 7 gauge U.S. Standard in mm?

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

Is 7 gauge U.S. Standard thicker than 6 gauge?

No — a lower gauge number is thicker sheet. 6 gauge us standard is 0.2031 in (5.159 mm) against 0.1875 in (4.763 mm) for 7 gauge U.S. Standard, a difference of 0.0156 in.

Why is 7 gauge a different thickness in other materials?

Because each material is indexed on its own gauge system. At 7 gauge: Aluminium 0.1443 in (B&S), Steel 0.1793 in (MSG), US Standard 0.1875 in (USG). The number is a position in a series, not a thickness, so 2 other readings of "7 gauge" are all equally correct.

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