Barcode Generator Check Digit Calculation

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Calculation of the Check Digit

EAN (European Article Number), UPC (Universal Product Code), ITF (Interleaved 2 of 5), and GTIN (Global Trade Item Number) barcodes are similar but have some differences. The algorithms used to calculate the check digits vary depending on the type of barcode. Although already covered on the page How is a Barcode Made, let’s see how to calculate the Check Digit using Modulo 10.

Generate EAN-13 Barcode (GTIN-13)

The check digit in the EAN code is calculated using an algorithm called Modulo 10.

Generate UPC-A Barcode (GTIN-12)

The check digit is calculated using an algorithm called Modulo 10.

ITF-14 Barcode (GTIN-14)

ITF uses a check digit calculation algorithm based on Modulo 10 or Modulo 11.

Modulo 10

Modulo 10 is a check digit algorithm used to calculate the check digits in barcodes such as EAN, UPC, and GTIN. This algorithm ensures data integrity in the barcode and helps detect any transcription or data corruption errors.

Here’s how the Modulo 10 check digit algorithm works:

1. Take the number to be checked, which can be a sequence of numerical digits;
2. Start from the second-to-last number in the sequence and move left, assigning an alternating weight of 3 or 1 to each digit. The first number has a weight of 3, the second has a weight of 1, the third has a weight of 3, and so on. This weight pattern repeats cyclically;
3. Multiply each digit by its corresponding weight;
4. Add up all the products obtained in the previous step;
5. Calculate the remainder of the sum divided by 10;
6. Subtract the calculated remainder from 10. If the remainder is 0, the check digit will be 0. Otherwise, the check digit will be the difference between 10 and the remainder.

For example, let’s consider the EAN-13 code “59012341234X”, where “X” is our Check Digit to be calculated:

Step 1: Take the numbers excluding the last one, so “59012341234”
Step 2: Assign weights starting from the end 3 1 3 1 3 1 3 1 3 1 3 1
Step 3: Multiply the respective numbers 12, 9, 0, 1, 6, 3, 12, 1, 6, 3, 12
Step 4: Sum of the products = 68
Step 5: Remainder of 68 / 10 = 8
Step 6: 10 – 8 = 2
Therefore, the check digit for the

EAN-13 code “59012341234X” is 2.

This Modulo 10 calculation process is used to ensure that the barcode contains the correct check digit and that the data is readable and valid.

Barcodes in Print

The EAN-13 or UPC-A symbols, in order to be correctly recognized by scanners, must be reproduced reflecting the nominal dimensions, allowing magnification factors between 80% and 200% as long as the width and height maintain their respective proportions.

EAN Barcode Printing Dimensions

GTIN-13 is also known as:

European Article Number 13
EAN-13 Supplement 5/Five-digit Add-On
EAN-13 Supplement 2/Two-digit Add-On
EAN-13+5, EAN-13+2, EAN13
EAN13+5, EAN13+2, UPC-13
GS1-13, EAN/UCC-13

UPC Barcode Printing Dimensions

GTIN-12 is also known as:

U.P.C.-A o Universal Product Code version A
UPC-A Supplement 5/Five-digit Add-On
UPC-A Supplement 2/Two-digit Add-On
UPC-A+5, UPC-A+2, UPC Code
UPC Symbol, GS1-12, UCC-12

Information about this Barcode Generator

This free online generator generates EAN-13 or GTIN-13 or UPC-A or UPC-12 or GTIN-12 barcodes, EAN or EAN-13 or GTIN-13 barcodes, and GTIN or GTIN-14 barcodes. You can copy and paste your desired code into the designated field and click the Generate! button. Your barcode will be ready in an instant!

What is a Barcode?

A barcode is a graphically represented numerical code that can be read by any device capable of optically scanning, such as a camera or a barcode reader. Barcodes are commonly applied to most products on the market.

What Barcode Represents a GTIN, EAN, or UPC Code?

It’s easy. Just type the code into the text box of our barcode generator and click the Generate! button. You should be able to see the image as soon as it’s ready.

How to Download the Barcode Image?

The barcode generated with our generator can be downloaded using the “Download” button or viewed on the screen.

Can I Print My Barcode?

Yes, absolutely. The generated barcode can be used completely free of charge for personal or commercial purposes. You can print it while always following the rules of the international standard.

What Types of Barcodes are Supported by the Generator?

This tool currently supports the following barcodes:

• UPC or UPC-A or UPC-12 or GTIN-12 Universal Product Codes – 12 digits
• EAN or EAN-13 or GTIN-13 European Article Numbers – 13 digits
• GTIN or GTIN-14 Global Trade Item Numbers – 14 digits

How Does Automatic Detection Work?

The generator is able to identify the barcode type and, if necessary, correct the check digit to produce the required barcode.