What is a UPU S10 number?

The Universal Postal Union standard for international postal and EMS items: two service letters, eight serial digits, a check digit, and a two-letter ISO country code of origin — for example RR123456785DE (a registered item from Germany). The 9th digit is a check digit, so a mistyped number is caught.

What do the first two letters mean?

They are the service indicator. R = registered, E = EMS/express, C = parcel, L = express letter, U = unregistered, V = insured. The last two letters are the country of origin (DE Germany, US United States, CN China).

Why can I not track a postal item end to end?

International post passes between two or more postal operators; visibility depends on each one publishing scans. TrackJet detects the S10 format, identifies the origin operator and routes you, and shows only events that have a real source.

Is the country code where it is going?

No — the two trailing letters are the country of origin (where the item was posted), not the destination.

Postal & EMS tracking (UPU S10)

Track an international postal or EMS item by its UPU S10 number. Paste it below — TrackJet reads the format, identifies the origin postal operator and routes you, showing only events that carry a real source. It never fabricates a scan.

The S10 format

The Universal Postal Union’s S10 standard gives every international item a 13-character identifier, for example RR 12345678 5 DE:

2 service letters — RR. The first letter is the service (R = registered); together they identify the product.
8 serial digits — 12345678. The item’s serial number.
1 check digit — 5. Computed from the eight serial digits (a weighted modulo-11 check), so a typo is caught.
2-letter country code — DE. The ISO country of origin — where the item was posted, not its destination.

Verified example numbers

Each of these passes the S10 check digit (they illustrate the format; they are not live items):

Number	Service	Origin
RR123456785DE	Registered	Germany
EE123456785US	EMS / express	United States
CP001122337CN	Parcel	China
RB987654326GB	Registered	United Kingdom
LX456789126FR	Express letter	France

What the service letter means

E	EMS / express mail
R	Registered
C	Parcel
L	Express letter
U	Unregistered / ordinary
V	Insured
Z	Insured (variant)

Why cross-border visibility varies

An international postal item passes between two or more postal operators — the sender’s, sometimes a transit one, and the destination’s. You only see a scan when an operator publishes it, so coverage is naturally patchier than a single courier. TrackJet detects the S10 format, identifies the origin operator and routes you, and shows only source-labelled events.

FAQ

What is a UPU S10 number?: The Universal Postal Union standard for international postal and EMS items: two service letters, eight serial digits, a check digit, and a two-letter ISO country code of origin — for example RR123456785DE (a registered item from Germany). The 9th digit is a check digit, so a mistyped number is caught.
What do the first two letters mean?: They are the service indicator. R = registered, E = EMS/express, C = parcel, L = express letter, U = unregistered, V = insured. The last two letters are the country of origin (DE Germany, US United States, CN China).
Why can I not track a postal item end to end?: International post passes between two or more postal operators; visibility depends on each one publishing scans. TrackJet detects the S10 format, identifies the origin operator and routes you, and shows only events that have a real source.
Is the country code where it is going?: No — the two trailing letters are the country of origin (where the item was posted), not the destination.