20 gauge steel thickness calculator
In the Manufacturers Standard Gauge for steel, 20 gauge is 0.0359 in (0.912 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
- 0.035 90
- Weight of the sheet
- 14.316
- Weight per square metre
- 7.158 kg/m2
- Weight per square foot
- 0.6650 kg/ft2
- Minimum inside bend radius One thickness is a safe general rule for mild steel; check the alloy.
- 0.912
- Bend allowance
- 2.034
- Bend deduction
- 1.614
- Suggested V-die opening Eight times thickness is the usual air-bending starting point.
- 7.29
Show the working
- Sheet length = 2000
- Sheet width = 1000
- Steel density = 7850
- Bend angle = 90
- K-factor = 0.42
- Thickness = 0.91186 = 0.911 86
- Thickness in inches = 0.911 86 / 25.4 = 0.0359
- area_m2 = 2000 * 1000 / 1e6 = 2
- volume_m3 = 2 * 0.911 86 / 1000 = 0.001 823 72
- Weight of the sheet = 0.001 823 72 * 7850 = 14.3162
- Weight per square metre = 0.911 86 / 1000 * 7850 = 7.1581
- Weight per square foot = 7.1581 * 0.09290304 = 0.665 009
- Minimum inside bend radius = 0.911 86 * 1 = 0.911 86
- Bend allowance = rad(90) * (0.911 86 + 0.42 * 0.911 86) = 2.033 93
- Bend deduction = 2 * (0.911 86 + 0.911 86) * tan(rad(90)/2) - 2.033 93 = 1.613 51
- Suggested V-die opening = 0.911 86 * 8 = 7.294 88
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 20 gauge steel?
0.0359 inches, or 0.912 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.