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Press brake punch forming sheet metal in a V die
Interactive tooling reference / Rev. 01
Prima Press USA / Bend force lab

Press Brake
Tonnage Calculator

Material, tooling, bend load, and machine reserve in one live setup.

Live bend load41.1US tons
Mild steelT 0.0598 inV 0.5 inL 120 in
049% of capacity100
Live bend cycle90 deg air bend
V 0.5 inT 0.0598 in
Active materialMild steel
Material thickness0.0598 in
V-die opening0.5 in
Capacity target49.3 US tons / 20% reserve
Bend force workstation / 01

Build the bend.

Set the stock, choose the tooling, and watch the machine load resolve in real time.

Calculation core activeAir bending / 90 degreesForce output / US tons
01
Input deckMaterial / geometry / capacity
Material
Material thickness

USS steel gauge. Gauge thickness is material-specific and nominal; verify actual stock before production.

V-die opening
Nearest standard opening1/2 in8.4x thickness
Bend length and capacity
Tooling matrix / Live reference

Air-bending tonnage chart

Mild steel / USS steel gauge / 60 ksi / values in US tons per linear foot

Calculated press brake tonnage per linear foot by material thickness and V-die opening.
Thickness1/4 in3/8 in1/2 in5/8 in3/4 in1 in1-1/4 in1-1/2 in2 in2-1/2 in3 in4 in5 in6 in8 in
20 ga0.0359 in
18 ga0.0478 in
16 ga0.0598 in
14 ga0.0747 in
12 ga0.1046 in
11 ga0.1196 in
10 ga0.1345 in
3/160.1875 in
1/40.25 in
5/160.3125 in
3/80.375 in
7/160.4375 in
1/20.5 in
5/80.625 in
3/40.75 in
7/80.875 in
11 in
6x-12x working rangeOutside typical range
Calculation basis / 02

Built on the standard 60 ksi air-bending relationship.

The calculator scales the baseline by the selected material tensile strength. The predicted radius and minimum flange are setup estimates; actual results depend on grain direction, material condition, tooling geometry, angle, and press-brake deflection.

Mild steel1.00x / 60 ksi
Stainless1.50x / 90 ksi
Aluminum0.50x / 30 ksi
F01Line load575 x thickness^2 / V opening x material factor
F02Total forceline load x bend length / 12
F03Capacity targettotal force x (1 + selected reserve)
Bending reference / 03

Press brake tonnage and V-die selection FAQ

Practical air-bending answers for estimating force and reviewing a setup before tooling and machine approval.

How is press brake tonnage calculated for air bending?

The calculator uses a 60 ksi mild-steel baseline of 575 times material thickness squared, divided by the V-die opening, to estimate tons per foot. It then applies the selected material factor and bend length.

What V-die opening should I use for air bending?

Eight times material thickness is a common mild-steel starting point, but the correct opening depends on material, thickness, flange length, inside-radius target, tooling geometry, and tooling load limits. The calculator selects from standard die openings and shows nearby alternatives.

Does bend length change required press brake tonnage?

Yes. Total bend force scales directly with bend length. A part twice as long requires approximately twice the total force when material, thickness, die opening, and bend method stay the same.

Is calculated bend tonnage the same as the machine tonnage I should buy?

No. The calculated load is a setup estimate. Machine selection must also consider working length, concentrated-load limits, tooling capacity, off-center loading, crowning, stroke, daylight, throat, controls, guarding, and an appropriate reserve.

Machine selection / 04

Turn the bend load into the right machine.

Use the result as the starting point for machine tonnage, working length, tooling, controls, crowning, material handling, and guarding review.