Press Brake Tonnage Calculator

Estimate press brake tonnage per foot for air bending from thickness, V-die opening, and material strength.

Air bending tonnage depends mostly on the die opening (the V-width), the material thickness, and the material strength. Wider V-dies need dramatically less force but give a larger minimum radius.

The result is force per unit length of bend — multiply by the bend length to get total tonnage, then confirm it is within the brake’s rating.

Formula: Tons/ft ≈ (575 × T²) / V (mild steel; scale by material factor)

Worked Example

  1. Bend 0.125 in mild steel in a 1.0 in V-die: Tons/ft ≈ 575 × 0.125² / 1.0 = 9.0 tons/ft.
  2. A 4 ft bend therefore needs about 36 tons.

Frequently Asked Questions

How is press brake tonnage calculated?

Air-bend tonnage per foot ≈ (575 × thickness² ÷ V-die width) scaled by material factor. Widen the V-die to lower tonnage.

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