Press Brake Tonnage Calculator
Estimate required press-brake force from material tensile strength, sheet thickness, bend length and V-die opening, then compare tooling method and machine capacity.
Press Brake Tonnage Calculator inputs
Choose material and units, then enter thickness, bend length, V-die opening, forming method and available machine capacity. U.S. and metric results are reported together.
Press Brake Tonnage Calculator results
How to use the press brake tonnage calculator
The press brake tonnage calculator evaluates an air-bending baseline from tensile strength, length, thickness squared and die opening. Explicit bottoming or coining multipliers are applied before the capacity margin is checked.
Air-bending force equation
The press brake tonnage calculator uses the common V-die air-bending relationship in which force is proportional to tensile strength, bend length and thickness squared, and inversely proportional to die opening. Metric inputs are converted to a base force in newtons before display in kilonewtons, metric tonnes-force and U.S. short tons.
Material and forming method
Material presets supply representative ultimate tensile strengths, while custom mode accepts the actual specification. Bottoming and coining require substantially more force than air bending, so the calculator applies clearly displayed method multipliers. Real requirements vary with tooling geometry, grain direction, lubrication, angle, radius and material batch.
V opening and inside radius
A common air-bending starting point is a V opening near six to ten times material thickness, depending on material and desired radius. The calculator reports V-to-thickness ratio and an approximate air-bend inside radius based on the die opening. It warns when the entered opening is unusually narrow or wide for a first-pass estimate.
Machine and tooling limits
Required tonnage must be checked against both the press-brake rating and the allowable concentrated load for the specific tooling and bed length. Off-center loads, short bends, hemming, multi-hit operations and worn tooling can create local overloads even when total machine tonnage appears adequate. Verify the job with the press and tooling manufacturers before production.
Press Brake Tonnage Calculator questions
Why does doubling thickness increase force so much?
The standard bending relationship contains thickness squared, so doubling thickness approximately quadruples required force when other inputs stay constant.
Does a wider V die reduce tonnage?
Yes, a wider opening reduces calculated force, but it also changes inside radius, flange requirements and bend accuracy.
Can I run at exactly the machine rating?
A calculation at or near rated capacity leaves little margin for material and tooling variation. Follow manufacturer limits and shop safety procedures.