How is the GS1 Modulo-10 check digit calculated?

Starting from right to left, alternate digits are multiplied by 3 and 1. The sum is calculated, and the check digit is the number required to bring this sum to the nearest multiple of 10.

What is GS1's Ambition 2027 for retail?

GS1's voluntary industry ambition is for retail POS systems worldwide to read and process the GTIN from existing linear and GS1-compliant 2D barcodes by the end of 2027. Processing additional data is a separate implementation step, and existing linear barcodes remain necessary during the transition.

Free GTIN Check Digit & GS1 Digital Link URI Builder

GTIN and URI fields

GTIN (8, 12, 13, or 14 digits) *

Check digit matches GTIN-13

Modulo-10 arithmetic matches · AI (01) representation: 08712345678906

Batch / lot (AI 10)

Expiry YYMMDD (AI 17)

HTTPS host controlled by the brand

The tool validates only the host shape; it does not configure a resolver or redirect.

GS1 Digital Link QR payload

The GS1 Digital Link parameters are invalid. Check the HTTPS host, lot, and expiry date.

Complete the valid parameters to generate a URI.

Prototype QR image. Retail POS use requires GS1-compliant HRI, dimensions, quiet zone, placement, print verification, and an end-to-end test with the intended scanners and POS software.

How the GTIN Modulo-10 check digit works

GTIN-8, GTIN-12, GTIN-13, and GTIN-14 contain a final Modulo-10 check digit. This tool checks that arithmetic only; it does not verify that GS1 issued the number or that it identifies the entered product.

1. Apply weights (3 and 1)

From right to left, excluding the check digit, multiply alternating digits by 3 and 1.

2. Calculate the sum

Add all weighted values to produce the total.

3. Complete the next multiple of ten

The check digit is the value needed to reach the next multiple of ten.

Check number assignment and product identity with Verified by GS1.