BENDORA TOOLS FOR SMARTER METAL FABRICATION

Press Brake Tonnage Calculator

Calculate the estimated tonnage required for 90° air bending based on material, sheet thickness, bend length, and V-die opening.

Press brake tonnage calculation for 90-degree air bending with punch and V-die tooling

Input Parameters

90° Air Bending

Material

Preset material factors are approximate. For greater accuracy, use the actual tensile strength for the material grade.

Tensile Strength

MPa

Enter the tensile strength for your actual material grade.

Sheet Thickness (T)

Material thickness to be bent.

V-Die Opening (V)

Width of the selected V-die opening.

Bend Length (L)

Total length over which bending force is applied.

Calculation Basis
The estimate is based on a standard 90° air-bending force formula referenced to mild steel with approximately 60,000 psi (414 MPa) tensile strength.

Calculation Results

Estimate Only

Estimated Required Force

18.6 US tons

≈ 16.8 metric tonnes-force

Tonnage per meter 18.6 US tons/m

Material factor 1.00

V / Thickness ratio 8.0 × T

Suggested V-die opening ≈ 12–16 mm

Selected Setup

Material Mild Steel

Thickness 2 mm

V-Die Opening 16 mm

Bend Length 1000 mm

Bending Method 90° Air Bending

Important Engineering Note The calculated value is an estimated bending force, not the press brake machine capacity that should automatically be selected. Actual requirements may vary with material properties, tooling geometry, bend angle, concentrated or off-center loading, machine condition and tooling limits. Always verify machine and tooling specifications before production.

Calculation Formula

Common 90° air-bending force estimate based on approximately 60,000 psi mild steel.

F = [575 × T² / (V × 12)] × L × Material Factor

F = Required bending force in US tons
T = Material thickness in inches
V = V-die opening in inches
L = Bend length in inches
Material Factor adjusts for actual tensile strength

≡

Material Factor Guide

Use actual tensile strength whenever reliable material data is available.

Material Factor

Actual Tensile Strength ÷ 60,000 psi

Tensile Strength	Factor
30,000 psi	0.50
60,000 psi	1.00
90,000 psi	1.50

i Do not assume one factor for every stainless steel or aluminum grade. Tensile strength can vary substantially by alloy, temper and condition.

V-Die Selection Guide

Typical starting points for 90° air bending, not fixed tooling requirements.

Application	Starting Point
Thin sheet or tighter radius	≈ 6 × T
General mild steel air bending	≈ 8 × T
Thick or higher-strength material	≈ 10–12 × T

i Final V-die selection also depends on material grade, required inside radius, minimum flange length, tooling capacity and bending conditions.

Tonnage Calculator Related Resources

Related Press Brake Calculation Guides

Use these engineering guides to understand the variables behind the calculator and evaluate your bending setup in more detail.

How to Calculate Press Brake Tonnage

Understand how material strength, thickness, bend length and V-die opening affect required bending force.

How to Choose the Right V-Die Opening

Learn how V-die opening affects tonnage, inside bend radius and minimum flange dimensions.

Press Brake Bend Radius

Understand the relationship between tooling, material thickness, V-die opening and the resulting bend radius.

Press Brake Bend Allowance

Calculate the developed length of a bent part using bend angle, radius, thickness and K-factor.

Go Beyond the Tonnage Calculation

Tonnage is only one part of press brake selection. Working length, material properties, tooling, bend geometry, backgauge requirements and production conditions should also be evaluated.