2026-11-02

Free barcode generator and GTIN check digit calculator (and what a valid check digit doesn't prove)

We've built a free barcode generator and GTIN check digit calculator. Type a GTIN, UPC or EAN and it tells you whether the last digit is right. If the number has no check digit yet, it works one out. Then you can download the barcode as SVG or PNG, or print a sheet of labels on A4 or US Letter. It runs in your browser, so the numbers you type never leave your computer.

Open the free barcode generator

What it does

• Checks the check digit on GTIN-8 (EAN-8), GTIN-12 (UPC-A), GTIN-13 (EAN-13) and GTIN-14 numbers. If it's wrong, it shows the digit that would be right.
• Generates a check digit for 7, 11, 12 or 13 digits.
• Draws the barcode that matches the number: EAN-13, UPC-A, EAN-8 or ITF-14 (for outer cartons). There's also Code 128 for your own stock codes, clearly marked as not a GTIN.
• Checks up to 100 numbers at once from a pasted spreadsheet column, with a CSV of the results.
• Prints label sheets. Match the paper, columns, rows and margins to your label stock (3 × 8 on A4 by default).

How the check digit works

The last digit of every GTIN is a check digit, calculated with GS1's mod-10 method. Starting from the digit just left of the check digit and moving left, multiply the digits by 3, 1, 3, 1 and so on, and add them up. The check digit is whatever brings the total up to the next multiple of 10.

Take 400638133393. The weighted total is 89, so the check digit is 1, and the EAN-13 is 4006381333931. Mistype one digit and the check digit no longer fits, which is how most typos get caught.

What a valid check digit doesn't prove

This is the part people miss. Any string of 12 digits can be given a valid check digit. A number that passes the check is well formed. It isn't necessarily registered, and it isn't necessarily yours.

A real GTIN is assigned to one product by its brand owner, using a GS1 company prefix: a block of numbers a business licenses from its local GS1 office (see gs1.org). If you resell branded goods, the GTIN is the number under the barcode on the pack. If you make the product, it only has a GTIN if you got numbers from GS1.

Google is clear on this. Its GTIN help page says not to guess or make up a value, and to only provide a GTIN if you're sure it's correct. It also lists ranges not to submit at all: restricted numbers starting 02, 04 or 2 (used for in-store labels such as weighed goods) and coupon numbers starting 05, 98 or 99. The tool flags numbers in those ranges.

Use the generator to catch typos and draw barcodes for numbers you already own, not to invent GTINs for Google Shopping.

If Merchant Center says "Missing or incorrect GTIN"

Google's GTIN page says products with a missing or incorrect GTIN may have limited visibility, and that a product which has a GTIN but doesn't submit it could be disapproved. Products that genuinely have no GTIN, such as handmade or one-of-a-kind goods, are handled differently. Our guide to the "Missing or incorrect GTIN" issue on WooCommerce covers where the numbers go and when to tell Google a product has none.

To see what else Google might flag on your store, run the free Merchant Center Check (about 60 seconds). If you'd rather hand the fixing over, Merchant Center Fix, done for you corrects product data and feed errors on up to 50 products, with a before/after log.

Printing labels that scan

Print at 100% scale ("Actual size", not "Fit to page"), with black bars on a white label. GS1's standard EAN-13 is about 37 mm wide and scanners are designed for roughly 80% to 200% of that, so keep EAN and UPC labels at least 30 mm wide. Print a test sheet on plain paper and scan it with your phone before a big run.

The barcodes are drawn by JsBarcode, an open-source library (MIT licence).