Used by 700,000+ people
Free UPU S10 barcode generator.
UPU S10 numbers identify registered, tracked, insured, EMS and parcel items between postal operators. Enter one and download its Code 128 barcode.
How to create a UPU S10 barcode
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01
Enter your operator's number
Type all 13 characters, or 12 and let the generator insert the check digit.
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02
Size it in printer dots
Choose Pixel under Module width and enter your printer's Resolution (dpi): 4 pixels at 300 dpi give 0.339 mm.
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03
Keep 3.4 mm clear
Leave this 10-module quiet zone free on each side in your layout. Apply the label flat, not around an edge.
What is a UPU S10 barcode?
UPU S10 is the Universal Postal Union's 13-character tracking number for one postal item: service indicator, serial number, check digit and issuing country. Printed as Code 128 with a plain-text line, it can be scanned by every operator on the route.
Where S10 numbers appear
The number sits on pre-printed labels, UPU forms such as CN 23 and CP 72, or labels customers print from an operator's shipping system.
The same characters go on CN 33 lists, customer receipts and CN 08 inquiries, and can be sent in PREDES and EMSEVT messages.
Code 128, check digit and print resolution
Operators must be able to scan Code 128 and Code 39, but S10 strongly recommends Code 128: it is more compact and detects read errors better. FNC4 is not permitted.
Customer service can check the digits of a number given by phone against the check digit. For digital printing, S10 recommends whole printer dots per bar and space, and 300 dpi or more.
One label online, volumes in TEC-IT software
GIF, PNG and JPG downloads are free; a plan adds SVG and higher print resolution. Serial ranges go into a data sheet after a free sign-in.
TBarCode SDK prints UPU S10 with its mod 11 check digit in your shipping software; TFORMer Server prints it from ERP label jobs.
UPU S10 at a glance
- Type
- Code 128 (Code 39 accepted)
- Format
- AANNNNNNNNNAA
- X-dimension
- 0.25–0.51 mm (at least 0.33 recommended)
- Bar height
- At least 9 mm and 15% of symbol width
- Quiet zone
- 10X at each end
S10 structure and check digit
| Characters | Content | Example |
|---|---|---|
| 1–2 | Service indicator: E EMS, R registered, L tracked, C parcel | EM |
| 3–10 | Serial number | 10002799 |
| 11 | Check digit | 5 |
| 12–13 | Issuing country, ISO 3166-1 | SE |
Weights 8 6 4 2 3 5 9 7 on 10002799 give 193; 193 mod 11 = 6, and 11 − 6 = 5. Results of 10 and 11 become 0 and 5.
Common S10 mistakes
- Keeping the generator's text line. At 300 dpi it sits under 1 mm below the bars, where S10 requires 1–5 mm and suggests spacing like EM 100 027 995 SE. Set it in your layout.
- Spaces or lower case. The generator refuses both.
- Inventing numbers. No identifier may be reused within 12 months; use your operator's range.
S10 and related barcodes
The symbology underneath, without S10's fixed format and mod 11 check.
USPS's digits-only GS1-128 package number.
Frequently asked questions
Learn more about UPU S10.
Where do I get UPU S10 tracking numbers?
Does the country code show where an item was posted?
Can a domestic shipment use an S10 identifier?
Can the generator print an S10 identifier in Code 39?
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