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General purpose alphanumeric format.
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Barcode Generator
Build clean, scannable barcodes with configurable format and styling, then export as SVG or PNG.
Preview
Encoded payload
QUONTLY-2026
Format: Code 128
Learn Barcode Formats and Checksums
Use this quick reference to choose the right format and avoid invalid check digits.
Code 128
- Character set
- ASCII letters, numbers, and symbols
- Length rule
- Variable length
- Checksum rule
- Internal barcode checksum only
- Common use case
- Internal labels, logistics, and general tracking
EAN-13
- Character set
- Digits only
- Length rule
- 12-digit base or 13-digit full value
- Checksum rule
- Last digit validates first 12 digits
- Common use case
- Global retail products
EAN-8
- Character set
- Digits only
- Length rule
- 7-digit base or 8-digit full value
- Checksum rule
- Last digit validates first 7 digits
- Common use case
- Small retail packaging
UPC
- Character set
- Digits only
- Length rule
- 11-digit base or 12-digit full value
- Checksum rule
- Last digit validates first 11 digits
- Common use case
- U.S. and Canada retail products
ITF-14
- Character set
- Digits only
- Length rule
- 13-digit base or 14-digit full value
- Checksum rule
- Last digit validates first 13 digits
- Common use case
- Cartons and outer packaging
MSI
- Character set
- Digits only
- Length rule
- Variable length
- Checksum rule
- Not required in this tool workflow
- Common use case
- Warehouse and inventory systems
| Format | Character set | Length rule | Checksum rule | Common use case |
|---|---|---|---|---|
| Code 128 | ASCII letters, numbers, and symbols | Variable length | Internal barcode checksum only | Internal labels, logistics, and general tracking |
| EAN-13 | Digits only | 12-digit base or 13-digit full value | Last digit validates first 12 digits | Global retail products |
| EAN-8 | Digits only | 7-digit base or 8-digit full value | Last digit validates first 7 digits | Small retail packaging |
| UPC | Digits only | 11-digit base or 12-digit full value | Last digit validates first 11 digits | U.S. and Canada retail products |
| ITF-14 | Digits only | 13-digit base or 14-digit full value | Last digit validates first 13 digits | Cartons and outer packaging |
| MSI | Digits only | Variable length | Not required in this tool workflow | Warehouse and inventory systems |
Checksum Basics
For retail and packaging formats, the final digit is a check digit. This tool can generate that digit from the base value, or validate it when you provide a full value.
EAN-13
Enter 12 digits to auto-calculate the check digit, or provide a full 13-digit value that already includes a valid check digit.
EAN-8
Enter 7 digits to auto-calculate the check digit, or provide a full 8-digit value with a valid check digit.
UPC
Enter 11 digits to auto-calculate the check digit, or provide a full 12-digit value with a valid check digit.
ITF-14
Enter 13 digits to auto-calculate the check digit, or provide a full 14-digit value with a valid check digit.
Valid and Invalid Examples
Try these values directly in the tool to see checksum validation in action.
EAN-13
- Base value
- 590123412345
- Valid full value
- 5901234123457
- Invalid full value
- 5901234123458
EAN-13 invalid example uses a wrong final check digit.
EAN-8
- Base value
- 5512345
- Valid full value
- 55123457
- Invalid full value
- 55123458
EAN-8 invalid example uses a wrong final check digit.
UPC
- Base value
- 03600029145
- Valid full value
- 036000291452
- Invalid full value
- 036000291453
UPC invalid example uses a wrong final check digit.
ITF-14
- Base value
- 1540014128873
- Valid full value
- 15400141288732
- Invalid full value
- 15400141288733
ITF-14 invalid example uses a wrong final check digit.
| Format | Base value | Valid full value | Invalid full value |
|---|---|---|---|
| EAN-13 | 590123412345 | 5901234123457 | 5901234123458 EAN-13 invalid example uses a wrong final check digit. |
| EAN-8 | 5512345 | 55123457 | 55123458 EAN-8 invalid example uses a wrong final check digit. |
| UPC | 03600029145 | 036000291452 | 036000291453 UPC invalid example uses a wrong final check digit. |
| ITF-14 | 1540014128873 | 15400141288732 | 15400141288733 ITF-14 invalid example uses a wrong final check digit. |
FAQ
Why do I only see the background and no bars?
The most common reason is an invalid full-length value for EAN-13, EAN-8, UPC, or ITF-14. Enter the base length and let the tool generate the check digit, or provide a full value with a valid check digit.
Should I enter the full value or base value?
Use the base value when possible. The tool will append a valid check digit automatically and reduce manual errors.
Can I use letters in retail barcode formats?
No. EAN-13, EAN-8, UPC, and ITF-14 accept digits only. Use Code 128 if you need letters or symbols.
What print settings help barcode scanners?
Use dark bars on a light background, keep sufficient margin, and avoid scaling very small. High contrast and clean edges improve scan reliability.