If you are an experienced thermal paper buyer, you know that different paper grades have different lengths for the same paper roll size. For example, for 80mm x 80mm paper roll, our most popular paper size, can be anywhere from 50 to 90 meters long! Thicker materials tend to be more durable and are perceived by customers as of higher quality. However, the thicker the material, the less paper per roll, resulting in fewer receipts that can be printed, which means you have to change the paper roll frequently in your printer.

Therefore, thickness and length are two key factors you should consider when buying paper rolls for your application. In this article, we will show you how to measure the paper thickness and how to calculate the paper roll length.

## Materials:

• A micrometer
• A ruler
• Thermal paper roll

## Firstly, You Need to Know the Paper Thickness:

Micrometer Source: Panda Paper Roll

The best way to measure the paper thickness would be with a micrometer or gauge, which comes in a few styles. You can tear some pieces of paper, choose multiple spots (at least 4) on the paper, and measure the thickness with your gauge (you can buy the gauge from us if you don’t have one). This will give you an average of a few location points, so you will not capture a high or low spot.

## Secondly, Do Some Simple Math Work:

From the above paper roll illustration, we can see the paper roll is essentially a cylinder. We can use a ruler to measure the paper roll width, diameter, and core size:

• A: paper width
• B: paper diameter
• C: core outer diameter
• T: paper thickness
• L: paper roll’s length

From the formula of cylinder volume, we can get the equation below: (If you want to know more about the logic behind this paper roll length calculator, you can check this link.)

A × L × T = πB²A ⁄ 4 – πC²A ⁄ 4

After simplifying, we can get the result:

L = (B² – C²) * 0.785 ⁄ T

This means if we know the paper roll diameter, core size, and paper thickness, we can get the paper length. (P.S: The paper roll length has no relationship with the paper width, no matter it is an 80mm width or 57mm width paper.)

Example 1:

For 80mm x 70mm x 13mm 60gsm thermal paper, the paper diameter (B) is 70mm, the core size (C) is 13mm x 17mm, and the 60gsm paper thickness (T) is 80um. Using the above formula, we can easily get the paper roll’s length 45m.

Example 2:

For 57mm x 40mm x 13mm 55gsm credit card paper rolls, the paper diameter (B) is 40mm, the core size (C) is 13mm x 17mm, the 55gsm paper thickness (T) is 60um. Using the above formula, we can get the paper roll’s length 18m.

Here below is an easy-to-use Excel tool for calculating paper roll length. If you want to calculate paper roll length online, we recommend using this online tool.

## Conclusion:

Don’t just pay attention to the price per roll, but also look at the cost per meter. The longer paper will be more cost-effective for you. Always consider the thickness and length factors when buying paper rolls to make sure you are getting what you pay for! If you are still looking for more information about thermal paper rolls, please do not hesitate to contact us at [email protected].

### About the Author: Frank Ouyang

Frank Ouyang is the sales manager at Panda Paper Roll Company - a leading factory of thermal paper rolls, label rolls, and other print-related products in China. With extensive experience in the industry, Frank is an expert in thermal paper knowledge and enjoys sharing his insights and expertise with clients, helping them achieve their goals and maximize their success.
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Nitin jain
1 year ago

Hii sir, would want to know how to convert gsm into UM for calculations. Your help and assistance shall be highly appreciated.

Ankit patel
1 year ago

Hellow how to calculate paper straw cost what is the formula

3 years ago

That is the um for 70 GSM

kazim raza
3 years ago

hello
i want formula how can i calculate paper length i have only paper gsm & paper width if any body know this matter pls let me

kazim raza
3 years ago

dear i want paper length i have only paper width & paper gsm

Gokul
4 years ago

Hlo what is the price of 3 inch paper roll at Indian price

2 years ago

Mahendra pawar
4 years ago

I want to purchase a guage for thickness checking

abdul rehman
4 years ago

How to get um if we know the GSM. What is the formula? 48GSM is equal to ? um

5 years ago

Thanks for pointing out that you’ll be able to calculate the length of the paper on the roll if you know the roll diameter, core size, and paper thickness. I was trying to help my daughter with a project for school, and she needed a certain length of plastic film from a roll. I wasn’t sure how to calculate the length, so thanks for sharing this guide!

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