9 gauge steel thickness calculator
In the Manufacturers Standard Gauge for steel, 9 gauge is 0.1495 in (3.797 mm). The gauge number counts down as the sheet gets thicker.
Where the neutral axis sits, as a fraction of thickness. 0.33 for tight bends, 0.5 for generous ones.
- Thickness in inches
- 0.149 50
- Weight of the sheet
- 59.618
- Weight per square metre
- 29.809 kg/m2
- Weight per square foot
- 2.7693 kg/ft2
- Minimum inside bend radius One thickness is a safe general rule for mild steel; check the alloy.
- 3.797
- Bend allowance
- 8.470
- Bend deduction
- 6.719
- Suggested V-die opening Eight times thickness is the usual air-bending starting point.
- 30.38
Show the working
- Sheet length = 2000
- Sheet width = 1000
- Steel density = 7850
- Bend angle = 90
- K-factor = 0.42
- Thickness = 3.7972999999999995 = 3.7973
- Thickness in inches = 3.7973 / 25.4 = 0.1495
- area_m2 = 2000 * 1000 / 1e6 = 2
- volume_m3 = 2 * 3.7973 / 1000 = 0.007 594 6
- Weight of the sheet = 0.007 594 6 * 7850 = 59.6176
- Weight per square metre = 3.7973 / 1000 * 7850 = 29.8088
- Weight per square foot = 29.8088 * 0.09290304 = 2.769 33
- Minimum inside bend radius = 3.7973 * 1 = 3.7973
- Bend allowance = rad(90) * (3.7973 + 0.42 * 3.7973) = 8.469 99
- Bend deduction = 2 * (3.7973 + 3.7973) * tan(rad(90)/2) - 8.469 99 = 6.719 21
- Suggested V-die opening = 3.7973 * 8 = 30.3784
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- weight = length x width x thickness x density
- bend allowance = angle in radians x (inside radius + K x thickness)
- bend deduction = 2 x (inside radius + thickness) x tan(angle/2) - bend allowance
Gauge numbers are not a single standard. Steel, aluminium, stainless and zinc all use different gauge tables for the same number, so always state the material.
The Manufacturers Standard Gauge descends from a weight-per-square-foot table, which is why the thicknesses are not a neat progression.
Frequently asked
How thick is 9 gauge steel?
0.1495 inches, or 3.797 mm, for uncoated sheet steel.
Is a higher gauge number thicker?
No. The gauge number counts down as thickness goes up, so 16 gauge is thicker than 20 gauge.
Where the numbers come from
- Thicknesses are the Manufacturers Standard Gauge for uncoated hot- and cold-rolled sheet steel.