A China Post international tracking number has 13 characters: 2 letters + 9 digits + 2 letters, ending in CN – for example RA123456789CN. The first letter tells you the service (E = EMS, R = registered, C = parcel, L = tracked small packet, U = limited tracking), and the last two letters are the country code.
The structure, character by character
China Post follows the Universal Postal Union’s S10 standard, the same format used by every UPU member country. That is why a number issued in China looks structurally identical to one issued by USPS or Royal Mail.
| Part | Characters | Meaning |
|---|---|---|
| Service indicator | 1-2 | Service family (E, R, C, L, U, V, A, H) |
| Serial number | 3-10 | 8-digit item number assigned by China Post |
| Check digit | 11 | Validates the number (Modulo-11) |
| Country code | 12-13 | Issuing postal operator – CN = China Post |
Example: LZ123456789CN
LZ= tracked letter post / small packet12345678= serial9= check digitCN= issued by China Post
What each prefix letter means
| Prefix | Service | Tracked abroad? | Typical use |
|---|---|---|---|
| E | EMS (Express Mail Service) | Yes, end-to-end | Urgent, high-value |
| R | Registered Mail (signed-for) | Yes, end-to-end | Small items needing proof |
| C | Parcel post / insured parcel | Yes | Heavier parcels |
| L | Tracked letter post / small packet | Usually | ePacket, e-commerce |
| A | E-commerce small packet | Often limited | Budget marketplace orders |
| U | Letter post under customs control | Often no | Economy, untracked mail |
| V | Insured letter | Yes | Declared-value mail |
| H | E-commerce parcel | Varies | Commercial e-commerce |
What the prefixes look like in the real world
We extracted every S10-format number from 50,037 real China Post tracking enquiries. The service mix is far more skewed toward budget channels than most guides suggest:
| First letter | Share of all numbers |
|---|---|
| L* (tracked small packet) | 36.7% |
| R* (registered) | 17.3% |
| A* (e-commerce packet) | 17.1% |
| E* (EMS) | 11.4% |
| C* (parcel) | 8.8% |
| U* (limited tracking) | 7.8% |
| V* (insured) | 0.2% |
The most frequently seen full prefixes were LZ (3,195), LY (2,955), RV (2,581), AM (2,169), AS (2,062), CP (2,022), LV (1,836), EV (1,643), LO (1,473), EB (1,403).
Why this matters to you: if your number starts with L or A, you are most likely on an economical e-commerce channel – which explains why your tracking may be thin after export. If it starts with E, you bought the fastest, best-tracked option.
The second letter is not a service level
A common myth: “RB is faster than RA” or “LZ is a premium version of LO”. Neither is true.
The first letter sets the service family. The second letter simply identifies which block of numbers the item was allocated from. So RA, RB and RC are all Registered Mail, and LZ, LO, LP, LX are all tracked letter post.
If someone tells you one variant is faster, treat it as anecdote. Transit time depends on route, customs and volume – not on the second letter.
The country code: the detail most people miss
The last two letters are not decorative. They identify which postal operator issued the number.
In our data, the country codes were:
| Code | Count | Operator |
|---|---|---|
| CN | 37,043 | China Post |
| US | 1,032 | USPS |
| SG | 894 | Singapore Post |
| GB | 711 | Royal Mail |
| NL | 437 | PostNL |
This is the most practical finding in the whole dataset. Over 3,000 numbers in a China Post helpdesk dataset were not issued by China Post at all.
Many Chinese sellers and consolidators route parcels through Singapore Post, PostNL, Royal Mail or USPS and hand the buyer a number ending in SG, NL, GB or US. The parcel still ships from China, but the tracking record belongs to a different postal operator – so China Post’s own site will show nothing, and you will wrongly conclude the number is fake.
Rule of thumb: if it does not end in CN, track it on the issuing operator’s site.
The check digit, and how to spot a typo
Character 11 is a checksum, calculated from the 8 serial digits using a fixed weighted formula. This is useful because a single mistyped character often fails this test – which is exactly why some valid-looking numbers return “not found”.
The weights for the eight serial digits are 8, 6, 4, 2, 3, 5, 9, 7. Multiply each digit by its weight, sum the results, divide by 11, then subtract the remainder from 11 (with remainder 0 becoming 5, and remainder 1 becoming 0).
A worked example. Take the serial 12345678. Multiply each digit by its weight:
| Digit | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|
| Weight | 8 | 6 | 4 | 2 | 3 | 5 | 9 | 7 |
| Product | 8 | 12 | 12 | 8 | 15 | 30 | 63 | 56 |
The products sum to 204. Divided by 11, the remainder is 6, and 11 − 6 = 5. So for this serial the eleventh character must be 5, giving LZ123456785CN. Any other character in that position means a typo or a fabricated number – which is why a single mistyped digit produces an instant “not found” rather than partial results.
You do not need to compute this by hand. Most tracking validators run the test automatically, and a failed checksum almost always means a typing error rather than a fake parcel.
Numbers that are not China Post numbers
Not every code a seller sends follows S10. Common look-alikes:
- Marketplace logistics IDs (often starting with
LP) – internal Cainiao or platform references, not postal numbers. - Pure numeric codes – usually domestic Chinese couriers (SF, YTO, ZTO, STO) or consolidation labels.
- Private courier numbers – DHL, FedEx and UPS use their own formats entirely.
- Domestic-only S10 blocks – some prefixes are reserved for domestic or bilateral use only.
If a number does not match 2 letters + 9 digits + 2 letters, it is not a standard China Post international tracking number, whatever the seller says.
How to confirm a number with the seller
If a number looks wrong, ask three specific questions:
- Which postal operator issued it? The answer must match the country code at the end.
- Can you send a photo of the shipping label? A photo settles typos instantly and removes all guesswork.
- Which service was used? The prefix should be consistent with the answer – EMS starts with E, ePacket with L, registered mail with R, parcel post with C.
Sellers who cannot answer these three questions are usually shipping through a consolidator. That is entirely legitimate, but it means the tracking record sits with a different operator – so ask which one, and track it there.
FAQ
Do all China Post tracking numbers end in CN?
No. Numbers issued by China Post end in CN, but Chinese sellers frequently use Singapore Post (SG), PostNL (NL), Royal Mail (GB) or USPS (US) – all of which look identical in structure.
Why does my number start with two letters but still show no results?
Either it has not been scanned yet, or it was issued by another operator. Check the last two letters first.
How many digits should a China Post tracking number have?
Thirteen characters in total when written in full: two letters, nine digits, two letters.
Is a 13-digit number with no letters a China Post number?
No. S10 numbers always contain letters. Pure-digit codes belong to couriers, consolidators or marketplace systems.
What does the letter A mean on a China Post number?
It belongs to the e-commerce small-packet family. In our data, A* numbers accounted for 17.1% of all numbers – and they dominate in “delivered but not received” complaints, because these channels often deliver without a signature.
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