Inputs
General purpose alphanumeric format.
Utilities
Barcode Generator
Build clean, scannable barcodes with configurable format and styling, then export as SVG or PNG.
Not sure which barcode standard fits your workflow? Use the Barcode Format Selection Guide before generating artwork.
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. |
Barcode Implementation Checklist
Use this checklist before printing production labels for retail, shipping, or inventory workflows.
Retail vs logistics format selection
Use retail standards for consumer-ready products and logistics standards for internal handling and carton labeling.
- Choose EAN-13, EAN-8, or UPC for point-of-sale retail workflows.
- Choose ITF-14 for outer packaging and carton-level scanning.
- Choose Code 128 for internal IDs that include letters and symbols.
Print calibration checklist
Scanner reliability usually depends on print quality more than encoded value.
- Maintain dark bars on a light background with high contrast.
- Do not compress bar width below scanner-friendly thresholds.
- Preserve quiet zones and avoid placing graphics too close to symbol edges.
Checksum troubleshooting workflow
When barcodes fail validation, verify base length and checksum rules before adjusting design settings.
- Start with the required base length for the selected format.
- Let the tool generate check digits whenever possible.
- If using full values, confirm the final check digit is valid for the first digits.
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.
How much quiet zone margin should I keep?
Keep clear space on both sides of the symbol. If surrounding graphics are too close, scanners can fail to detect the barcode boundary.
Can I use barcode colors other than black?
Yes, but keep strong contrast. Dark foreground on light background is safest. Avoid light bars, gradients, and reflective materials.
What is the difference between EAN-13 and UPC?
Both are retail formats. UPC is common in U.S. and Canada retail workflows, while EAN-13 is used globally and includes a country or region prefix model.
When should I use ITF-14 instead of EAN or UPC?
Use ITF-14 for shipping cartons and outer packaging. Use EAN or UPC for the individual consumer unit sold at checkout.
Why does the barcode scan on one device but not another?
Scanner engines vary by hardware and software. Improve reliability by increasing print size, preserving margins, and maximizing contrast.
Should human-readable text always be shown under the bars?
For many retail and operational workflows it helps manual verification. Hide it only when layout constraints require it and scanning remains reliable.
Can this tool verify GS1 registration or product ownership?
No. This tool validates formatting and checksum rules only. GS1 assignment and ownership checks require your official numbering workflow.