EAN / UPC check digit calculator

Enter the data digits of an EAN-13, UPC-A, EAN-8 or GTIN-14 and get the check digit and the full number instantly — the calculation runs in your browser.

Enter the number without its check digit.

Check digit
–

Open in the generator to size & download →

How to calculate a check digit

  1. Pick the format — EAN-13, UPC-A, EAN-8 or GTIN-14.
  2. Type the number without its final check digit.
  3. Click Calculate check digit to see the check digit, the completed number and its barcode.

How the EAN / UPC check digit works

EAN-13, UPC-A, EAN-8 and GTIN-14 all use the same GS1 modulo-10 algorithm. Reading the data digits from right to left, each is multiplied by an alternating weight of 3 and 1 (rightmost data digit ×3). The products are added together, and the check digit is the number you must add to reach the next multiple of ten.

Worked example (EAN-13). For data digits 400638133393, the weighted sum is 47; the next multiple of ten is 50; so the check digit is 3, giving 4006381333931. Scanners repeat this calculation on every read to reject a mistyped number.

Why it matters

The check digit is a built-in typo detector. If you key a number by hand or receive it from a supplier, calculating the check digit confirms the number is internally consistent before you print thousands of labels. To check a complete number you already have, use the barcode verifier; to produce the barcode, use the matching generator such as the EAN-13 generator.

The check digit is not the whole number. Calculating it does not create a registered GTIN. For retail sale, the number itself is assigned by GS1. This tool only completes and validates the math.
EAN-13 generator UPC-A generator Verify a barcode All barcode types

Frequently asked questions

What is a check digit?

The last digit of an EAN, UPC or GTIN, calculated from the preceding digits. Scanners recompute it on every read to catch a mistyped or misread number.

How is the EAN/UPC check digit calculated?

Each digit is multiplied by an alternating weight of 3 and 1 (starting with 3 from the rightmost data digit), the products are summed, and the check digit is the amount needed to round that sum up to the next multiple of ten.

Which formats does this calculator support?

EAN-13 (enter 12 digits), UPC-A (11), EAN-8 (7) and GTIN-14 / ITF-14 (13). All four use the same GS1 modulo-10 algorithm.

Does the calculator send my numbers anywhere?

No. The calculation runs entirely in your browser; nothing is uploaded.

Can I turn the result into a barcode?

Yes — the calculator shows the barcode for the completed number, and you can open the matching generator to size and download it.

Why does my number fail validation elsewhere?

If a full number's last digit does not match the calculated check digit, it was mistyped or invalid. Re-enter the data digits here to find the correct check digit.