The Tube Form Solutions Blog

Tube Bending Section Modulus Calculator

Posted by Mike Thomas on 3/1/17 4:02 PM

Calculating the section area moment of inertia properties of common shapes for tube bending and fabricating metal into finished shapes can be time consuming and complicated. Which is why we’ve created a free Tube Section Modulus Calculator. 


What is the section modulus?

Typically, structural engineers designing “I” beams or T beams calculate section modulus of the cross-sectional area of the beam to understand if the beam will support a particular load or repeated cyclic loading. This is so that building, bridges, and rail road tracks do not fail and have safety factors.

However, section modulus can also relate to bending tubes. When bending tube or pipe, the bender must have enough bend arm toque to overcome a material’s section modulus to make a bend into the tube that is permanent.  Also, the material composition determines the deforming of the tubing material past the given material’s modulus of elasticity and into the yield strength of the material. 

Determining the section modulus of the piece of tube or pipe you need to bend is important because it will allow you to know before you bend if your equipment can successfully complete the bend.

What happens if you are not bending round tubes?

How do you know what bender will bend your square, rectangle, non-round shape?  You need to calculate the section area moment of inertia for the round material and compare it to your non-round material.  As long as the round material number is higher than the non-round material, then that particular bender will be capable of bending your part shape.

What shapes are covered in the calculator download?

The tube bending section modulus calculator allows you to input the tube specifications into an easy to use calculator. It then calculates the section area moment of inertia properties of common shapes. Some of the most common shapes covered by the calculator are:

  • 2b-series-heavy-duty-cnc-benders.pngSquare
  • Round
  • Half rounds
  • Triangles
  • Rectangles
  • Trapezoids
  • Hexagons
  • Octagons

What is in the Tube Bending Formulas Guide?

The Tube Bending Formulas Guide that is bundled with the calculator covers some of the most common tube bending formulas, including:

  • Tube inside diameter
  • Wall factor
  • Mandrel nose radius
  • Clamp length

How to use these download

Together these two downloads are a powerful tool. They can help you evaluate your current equipment, determine if you can accomplish a bend that a new customer or RFQ has requested, evaluate your current equipment’s capabilities versus a new piece of equipment, and ensure you have the correct calculations before you begin a bend.

Where can you find the both the calculator and the guide?

Click here or follow the link below to download the Tube Section Modulus Calculator.

The article was originally published on April 7, 2016 and has been updated for accuracy.

Download the Tube Section Modulus Calculator


Topics: Tube Bending