Calculate bending force, inner radius and minimum flange length

Sheet metal bending calculator

Our online calculator allows you to determine sheet metal bending parameters within seconds accurately. Enter your project data and instantly get tonnage, inner radius and minimum edge.

Die opening

The die opening is usually chosen according to the thickness of the sheet metal, with this rule:

Thickness < 6 mm
die opening = thickness × 8

Thickness > 6 mm
die opening = thickness × 10

Clearly, the die opening can also be chosen with an opening greater or smaller than the ideal value, depending on the minimum flange length and internal radius to be obtained.

It should always be borne in mind that a die-to-thickness ratio of less than 8 generates a lower springback. At the same time, however, it increases the bending force required and causes greater stress. This increases the risk of cracks or even damage to material and equipment.

Minimum flange

The minimum flange length is the shortest rest length that can be achieved with a given die opening and for a given bend angle, without the material falling in. Unlike most bending rules, we have considered the outer face in our calculator because it is more convenient to measure.

Bending radius

The inner radius of the bent part depends substantially on the die opening and, to a lesser extent, the strength of the material.

In this calculator, we use the figure for the ultimate tensile strength of sheet metal. Here is a table with approximate values for the ultimate tensile strength of some of the most commonly used materials:

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