Sheet Metal and Welding Calculators
These calculators cover fabrication from flat blank to finished part: bend allowance, bend deduction and flat length using the K-factor, the weight of sheets and plates, the thickness a gauge number means for steel, stainless, aluminium and galvanised sheet, the flat pattern for a cone or truncated cone, the press brake tonnage for an air bend, the force to punch a hole and the size and strength of a fillet weld.
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All Sheet Metal & Welding (7)
Bend Allowance Calculator
Bend allowance, bend deduction and flat length using the K-factorSheet Metal Weight Calculator
Weight of sheet and plate by material, gauge and sizeSheet Metal Gauge Converter
Convert sheet metal gauge numbers to thickness for each materialCone Flat Pattern Calculator
Flat layout of a cone or truncated cone for rolling sheet metalPress Brake Tonnage Calculator
Bending force for air bending by thickness, die opening and materialPunching Force Calculator
Force to punch or blank a hole from perimeter, thickness and shear strengthWeld Size Calculator
Fillet weld strength, size and filler metal needed
Which tool do I need?
Work out the flat length of a bent bracket
Enter the flange lengths, thickness, inside radius, angle and K-factor to get the bend allowance and flat blank size.
Convert 16 gauge to millimetres
Pick the material and gauge to get the thickness in inches and millimetres and the weight per area.
Check that a press brake can make a bend
Enter the thickness, length, die opening and material to get the tonnage needed.
Lay out a cone or reducer from sheet
Enter the diameters and height to get the flat pattern radii and arc angle.
About Sheet Metal & Welding
Gauge tables differ by material, so the converter keeps them separate, and material presets give typical tensile and shear strengths that you can replace with your mill certificate values. Press brake tonnage uses the standard air-bending formula, and fillet weld strength follows the throat-area method used in AWS D1.1 and AISC.
Results are for checking, learning and preliminary design. Anything that carries load, current, pressure or people must be confirmed by a qualified engineer or licensed tradesperson against the code that governs your project.
Guides
- Bend Allowance, Bend Deduction and the K-Factor ExplainedWhere the neutral axis sits in a bend, how bend allowance, setback and bend deduction relate, how to measure your own K-factor from a test strip, and why tight air bends need a smaller K.
- How to Calculate Sheet Metal Weight (and Why Gauge Tables Disagree)Volume times density in metric and inch units, typical densities for steel, stainless, aluminium and copper, why gauge weight tables run 2% heavy, and what changes real weights.
- Sheet Metal Gauge Charts Explained: Steel, Galvanized, Stainless, AluminiumWhy one gauge number means four different thicknesses, where the Manufacturers’ Standard Gauge, the 1893 US Standard Gauge and Brown & Sharpe come from, and how to order sheet without gauge mistakes.
- How to Lay Out a Cone or Truncated Cone Flat PatternThe geometry of developing a cone, layout radius and arc angle formulas, mean diameters for thick plate, marking out, splitting into segments, and when triangulation is needed.
Frequently asked questions
What K-factor should I use for bend allowance?
Around 0.33 to 0.45 for most air-bent steel and aluminium, lower for tight radii and higher for large radii. Bend a test piece and measure it to find the value for your tooling and material.
Why does 16 gauge steel have a different thickness than 16 gauge aluminium?
Gauge numbers come from separate historical weight-based systems for each metal, so the same number gives a different thickness. Always specify the material with the gauge, or give the thickness directly.
How is fillet weld strength calculated?
From the throat, about 0.707 times the leg size, times the weld length and the allowable shear stress of the filler metal. The calculator shows each step.
Do I need bend allowance or bend deduction for my drawing?
Bend allowance is the length of the neutral axis through the bend, added to the flat legs. Bend deduction is the amount subtracted from the sum of the outside flange lengths. Both give the same flat blank.