Enter the material thickness, bend radius, and kerf width into the calculator to determine the kerf bend allowance.

Kerf Bend Formula

The following formula is used to calculate the kerf bend allowance for a given material and bend radius:

 KBA = (2 * π * t * (R + K)) / 360


  • KBA is the kerf bend allowance
  • t is the material thickness
  • R is the bend radius
  • K is the kerf width

To calculate the kerf bend allowance, multiply the material thickness by the bend radius and add the kerf width. Multiply the result by 2π (approximately 6.28) and divide by 360.

What is a Kerf Bend?

A Kerf Bend is a technique used in woodworking and metalworking to create a bend in a solid material. This is achieved by making a series of cuts, known as kerfs, along the line where the bend is desired. These kerfs remove a small amount of material, which allows the remaining material to bend without breaking or cracking. The depth and spacing of the kerfs determine the flexibility and radius of the bend. This technique is often used in furniture design and manufacturing, as well as in the creation of custom shapes for architectural and artistic applications. It is particularly useful when working with thick or rigid materials that would otherwise be difficult to bend.

How to Calculate Kerf Bend?

The following steps outline how to calculate the Kerf Bend:

  1. First, determine the thickness of the material (T). 
  2. Next, determine the bend radius (R). 
  3. Next, gather the formula from above = KB = 0.0175 * T * R.
  4. Finally, calculate the Kerf Bend.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

thickness of the material (T) = 0.5

bend radius (R) = 2