2 prefixes · shipping line
HMM container prefixes: HMMU, HDMU
Track on hmm21.com — official HMM tracker
Full HMM container tracking guide →
HMMU and HDMU are the BIC owner prefixes registered to HMM. A container number that starts with any of them belongs to the HMM fleet and is tracked free at hmm21.com. The eleventh character of the number is a check digit; it is worked out below for each prefix.
HMM, formerly Hyundai Merchant Marine, is South Korea’s national container line and the operator of some of the largest 24,000-TEU vessels ever built.
Its two codes reflect the rebrand: the newer HMM registration circulates beside the Hyundai-era one, both tracked on hmm21.com.
4 letters + 7 digits, printed on the doors. It is on your bill of lading too.
The answer appears as you type. Nothing is sent anywhere.
All 2 HMM prefixes
| Prefix | A valid number | Check digit | Where the code comes from |
|---|---|---|---|
HMMU | HMMU 565761-5 | 5 | — |
HDMU | HDMU 386248-5 | 5 | — |
Prefix register verified against two independent sources on 2026-08-03. The example numbers are computed to show the arithmetic. They are valid by construction, not numbers we saw on a box.
Data: BIC Container Prefix Register · ISO 6346:2022
HMMU: check digit, worked through
HMMU is registered to HMM. Take HMMU 565761-5: each of its first ten characters has a value and a weight, the products are added, and the remainder after dividing by 11 is the check digit — here 5.
| Character | Value | Weight | Product |
|---|---|---|---|
H | 18 | ×1 | 18 |
M | 24 | ×2 | 48 |
M | 24 | ×4 | 96 |
U | 32 | ×8 | 256 |
5 | 5 | ×16 | 80 |
6 | 6 | ×32 | 192 |
5 | 5 | ×64 | 320 |
7 | 7 | ×128 | 896 |
6 | 6 | ×256 | 1536 |
1 | 1 | ×512 | 512 |
Sum 3954 → 3954 mod 11 = 5 → check digit 5 → HMMU 565761-5
HDMU: check digit, worked through
HDMU is registered to HMM. Take HDMU 386248-5: each of its first ten characters has a value and a weight, the products are added, and the remainder after dividing by 11 is the check digit — here 5.
| Character | Value | Weight | Product |
|---|---|---|---|
H | 18 | ×1 | 18 |
D | 14 | ×2 | 28 |
M | 24 | ×4 | 96 |
U | 32 | ×8 | 256 |
3 | 3 | ×16 | 48 |
8 | 8 | ×32 | 256 |
6 | 6 | ×64 | 384 |
2 | 2 | ×128 | 256 |
4 | 4 | ×256 | 1024 |
8 | 8 | ×512 | 4096 |
Sum 6462 → 6462 mod 11 = 5 → check digit 5 → HDMU 386248-5
Tracking a HMM container
The tracker at hmm21.com ignores a number passed in the link, which we confirmed in a browser. Open it and paste the number into the form.
| Container number | ✓ yes |
|---|---|
| Bill of lading (B/L) | ✓ yes |
| Booking reference | ✓ yes |
| Mobile app | ✓ yes |
| Pre-filled link | — tried it: the page ignores a number in the link |
| Its bill of lading starts with | HDMU |
Browser-verified 2026-08-03
Can you see where the ship is?
Not from the container. A standard dry box has no power, no radio and no satellite receiver — it is a steel case with a number painted on it, and it reports nothing about itself. Every position you see against a HMM shipment was reported by something else: a terminal crane, a gate reader, or the ship.
A live map on a carrier’s tracking page is almost always plotting AIS, the transponder every large vessel broadcasts with its position, course and speed. That is genuinely useful at sea: it is a real position rather than a schedule, and an ETA recalculated from actual movement. It is also the ship’s position, not your box’s, and the two part company the moment the container is discharged.
On land the map goes quiet. Between the gate-out and the delivery there is no vessel to follow, and the road leg appears only as whatever events the terminal and the trucker report. A container sitting on a chassis in a yard shows the last position of a ship it left days ago. Only specialised IoT equipment reports its own location, and wherever that exists it is a paid product sold to the shipper, not something a tracking page gives away.
Frequently asked questions
Who owns HMMU and HDMU containers?
HMM does, a shipping line founded in 1976 — the BIC register lists 2 owner prefixes under it: HMMU and HDMU.
How do I track a HMMU container?
Free, on the official HMM tracker at hmm21.com — paste the full 11-character number; no account is needed. The same tracker serves all 2 HMM prefixes.
Why does HMM have 2 prefixes?
Because one prefix holds only a million serial numbers and a fleet outgrows it — and because a line that buys another line keeps the codes painted on the boxes it bought. All 2 are tracked on the same hmm21.com system.
Is HMMU a shipping line prefix or a leasing prefix?
A shipping line prefix — HMM both owns the box and moves it, so the owner and the tracker are the same company.
Is HMMU5657615 a valid container number?
Yes — HMMU 565761-5 passes the ISO 6346 check: the weighted sum for HMMU565761 leaves a remainder of 5 when divided by 11, which gives check digit 5. It is an example computed for this page, not a box we have seen.
One page, every owner code
Know whose box it is before you search
All 85 owner prefixes mapped to their line or leasing company, with the leased ones marked — so you can tell at a glance when to track with the line instead. Container dimensions are on page two.
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