UPC Barcode Checker
Validate UPC-A, EAN-13 and EAN-8 barcodes by their check digit, generate a missing check digit, or validate many codes at once. Everything runs in your browser — nothing is uploaded.
12 digits = UPC-A, 13 digits = EAN-13, 8 digits = EAN-8. Spaces and hyphens are ignored.
How the check digit is calculated
| # | Digit | Weight | Product |
|---|---|---|---|
| Sum | |||
11 digits for UPC-A, 12 digits for EAN-13, 7 digits for EAN-8.
Complete barcode:
Check digit: | Format:
| Code | Format | Result |
|---|
How to use
- Open the Validate tab and type a full barcode number.
- Press Check — you get a valid/invalid verdict plus the full digit-by-digit weighting table.
- Missing the last digit? Use the Generate tab with the remaining digits.
- Paste many codes into the Batch tab to check them all at once.
How the check digit works
- UPC-A (12 digits): multiply digits alternately by 3 and 1 from the left, add them up, and the check digit is (10 − sum mod 10) mod 10.
- EAN-13 (13 digits): same idea with weights 1 and 3 alternating from the left.
- EAN-8 (8 digits): weights 3, 1, 3, 1, 3, 1, 3, 1 from the left.
- A UPC-A code is also valid as an EAN-13 code with a leading zero, because the math is identical.