Enter the length of the bend, the tensile strength, material thickness, and unsupported material length into the calculator to determine the bend force.

Bend Force Formula

The following equation is used to calculate the Bend Force.

BF = (k*L*St*t^2) / d

  • Where BF is the bend force (lbs)
  • k is a constant based on the die shape (1.33 for V dies)
  • L is the length of the bend (in)
  • St is the tensile strength of the material (lb/in^2)
  • d is the unsupported material (die opening) (in)

What is a Bend Force?


A bending force is a total force required to bend a material with a particular die shape and opening.

How to Calculate Bend Force?

Example Problem:

The following example outlines the steps and information needed to calculate Bend Force.

First, determine the k constant. In this example, we are using a v die, so the constant is 1.33.

Next, determine the length of the bend. This bend is measured to be 3 inches.

Next, determine the tensile strength of the material. The tensile strength is calculated to be 50 lbs/in^2.

Next, determine the material thickness. In this case, the material thickness is 1.5 inches.

Next, determine the die opening size. For this problem, the unsupported material is 8 times the thickness = 12 inches.

Finally, calculate the bend force using the formula above:

BF = (k*L*St*t^2) / d

BF = (1.33*3*50*1.5^2) / 12

BF = 37.406 lbs