Calculate or validate the final digit of EAN-8, UPC-A, EAN-13 and GTIN-14 numbers. See every step of the calculation, entirely in your browser.
Complete a number or check its final digit.
No barcode image is needed.
Calculated check digit
This checks the arithmetic only. It does not verify whether a number is assigned to a product.
Your result will appear here.
| Position from left | Digit | Weight | Product |
|---|
Method: GS1 check digit calculation ↗
Your number and calculation stay on your device. This tool needs no external libraries, uploads, account or product database. Leading zeros remain intact, and the calculation is shown so you can inspect the result.
Starting at the rightmost base digit, multiply digits alternately by 3 and 1, then add the products. The check digit is the amount needed to reach the next multiple of 10. If the sum is already a multiple of 10, the check digit is zero.
No. A match confirms the arithmetic only. It does not verify GS1 assignment, ownership, product details or barcode print quality. If the digit does not match, the suggested number assumes all base digits were entered correctly.
Yes. Numbers are handled as text, so leading zeros are kept. Outer whitespace is trimmed. Embedded spaces, hyphens and digits outside 0–9 are rejected.
This tool supports only the GS1 modulo-10 check digit used by EAN-8, UPC-A, EAN-13 and GTIN-14. Code 128 uses a different checksum. UPC-E expansion and other barcode formats are not supported.
