Roll Length Tools

Created By : Bhagya
Reviewed By : Rajashekhar Valipishetty
Last Updated at : Oct 9,2023

Use this user-friendly roll length calculator tool that calculates the length of the roll easily in a blink of an eye. For that, you need to give the inner diameter, outer diameter, thickness as inputs and then click on the calculate button so that you will get the answers effortlessly.

Inner Diameter, d
Outer Diameter, D
Thickness, T

Roll Length Tools: Finding the length of the roll is not a difficult thing? If you are interested to know how to calculate the length of the roll manually then you are on the right page. And we also have an option on this page is you can use our roll length calculator tool for quick results or you can use this calculator to check the manual answers is correct or not. 

We have also provided steps to calculate the roll length manually, definitions, formulas, and some solved examples.

How to Calculate the Length of the Roll?

Roll length can be defined as the length of the material that is in the form of a roll with a given material thickness.

Roll Length 

Roll length formula, We will look into the formula to find the length of the roll.

L = (π * ((D2/4)-(d2/4))) / T


D is the outer diameter of the roll.

T is the material thickness.

π is the constant (3.141592654).

L is the length of the roll.

d is the inner diameter.

Now, here we can see the step-by-step procedure to determine the length of the roll manually.

  • Initially, write the given values that were given in the problem.
  • In the formula, first, we need to find the square of the outer diameter, i.e., π * (Diameter2/4).
  • Then, you need to subtract the result with a square of the inner diameter, i.e., π * ((D2/4)-(d2/4)).
  • After that, you need to divide the result by material thickness. i.e., (π * ((D2/4)-(d2/4))) / T.
  • Finally, you will see the length of the roll.


Question: Suppose you have a cylindrical material with an inner diameter of 150nm, an outer thickness of 200nm, and the material is 0.07 thick. Find the length of the cylindrical material?


Given, d = 150nm

D = 200nm, T = 0.07, L = ?

Apply the formula, 

L = (π * ((D2/4)-(d2/4))) / T

Substitute the values in it.

L = ((π * (2002 / 4)) - (1502 / 4)) / 0.07

= (3.14 * (40000 /4)) - (22500/4)) / 0.07

= (31400 - 5625) / 0.07

 = 368214.28 mm.

Therefore the length of the cylindrical material is 368214.28 mm.

More best maths calculators along with the concept are available on the website

FAQs on Roll Length Tools

1. What is Roll length?

The length of the material that has been rolled and in the form of cylindrical with the given material thickness then it is called roll length.

2. How to find the length of the cylindrical material(Roll)?

To find the length of the roll we can use the formula, L = (π * ((D2/4)-(d2/4))) / T.

3. How to use this roll length calculator?

How to calculate length of a roll from diameter? Just simply give the inner and diameters and the material thickness as inputs and then tap the calculate button you will see the output in seconds.

4. Calculate roll length from diameter formula?

How to calculate roll length, The formula for calculating roll length from diameter is:

Roll length = π * (diameter^2 / 4 - core diameter^2 / 4) / thickness

π is a mathematical constant with a value of approximately 3.14
diameter is the diameter of the roll in the same units as the thickness
core diameter is the diameter of the core of the roll in the same units as the thickness
thickness is the thickness of the material on the roll in the same units as the diameter
To use the formula, simply plug in the appropriate values for the diameter, core diameter, and thickness. The result will be the roll length in the same units as the thickness.

For example, if you have a roll of paper with a diameter of 10 inches, a core diameter of 2 inches, and a thickness of 0.01 inches, then the roll length would be:

Roll length = π * (10^2 / 4 - 2^2 / 4) / 0.01 = 314.15 inches
Therefore, the roll of paper would be approximately 314 inches long.

It is important to note that this formula is only an approximation. The actual roll length may vary depending on the material and the way it is rolled.

5. Roll diameter to length calculator?

Here are some tips for using a roll diameter to length calculator:

  • Make sure that you enter the values in the correct units.
  • If you are using a directional fabric, make sure to factor that into your calculations.
  • If you are unsure about how to use the calculator, there are typically instructions available on the website or in the app.
  • With a little planning, you can easily calculate roll length from diameter using a formula or a roll diameter to length calculator.