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Press Brake Tonnage Calculator

Work out press brake tonnage instantly with clear inputs, formula shown and shareable results.

About Press Brake Tonnage Calculator

Air bending force per metre is roughly 1.33 x tensile strength x thickness squared divided by die opening. Thickness dominates because it is squared, and a wider die reduces force but increases the bend radius, so the usual compromise is a die opening of six to eight times the thickness.

Formula

Air bend force

kN per metre = 1.33 x Rm x t² / V

Rm
Tensile strength, MPa
t
Thickness, mm
V
Die opening, mm

Worked example

With the default values below, Press Brake Tonnage Calculator returns Bending force required of 18.54. Change any input above and every figure here is recalculated in your browser.

Inputs used

Material thicknessminimum 0.1 mm
2 mm
Die opening (V)minimum 1 mm
12 mm
Bend lengthminimum 1 mm
1,000 mm
Material tensile strengthminimum 50 MPa
410 MPa

Results

Bending force required
18.54 t
Bending force
181.8 kN
Force per metre of bend
181.8 kN/m
Die opening to thickness ratio
6.00

Step by step

  1. 1Values used
  2. 2Air bend force
  3. 3Bending force required= 18.54 t
  4. 4Bending force= 181.8 kN
  5. 5Force per metre of bend= 181.8 kN/m
  6. 6Die opening to thickness ratio= 6.00

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Preliminary estimate only. Confirm tonnage and tooling capacity against the press brake and tooling manufacturer's data before forming.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Confirm tonnage and tooling capacity against the press brake and tooling manufacturer's data before forming.

Frequently Asked Questions

How is the Press Brake Tonnage figure worked out?

kN per metre = 1.33 x Rm x t² / V. Air bending force per metre is roughly 1.33 x tensile strength x thickness squared divided by die opening.

Why does coining need so much more force?

Air bending only bends the sheet; coining forces the material into the die to set the radius permanently, which takes roughly five to ten times the tonnage.

What values do I need to enter?

This calculator takes 4 inputs: Material thickness, Die opening (V), Bend length, Material tensile strength. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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