UN packaging

UN packaging code decoder

Read the UN packaging mark before the carrier rejects the booking.

A packaging mark that does not match the packing group of the cargo is a hard rejection at the carrier acceptance check. Ship Packing Group I goods in a Y-rated drum (built for PG II/III) and the booking unwinds at the terminal, with the cargo already trucked in. The mark on the drum is the only proof the packaging is certified for the contents.

Paste a UN packaging code (1A1, 4G, 5H2, 6HA1, etc). The tool decodes kind (drum, box, bag, IBC), material (steel, plastic, fibreboard, paper), category (closed-top, open-top), the X/Y/Z packing-group rating, the density or gross-mass limit, and the year of manufacture. Cross-check the decoded packing group against the cargo's UN entry before booking.

Last updated 2026-05-09. Math runs in your browser, no data leaves your computer.

UN packaging codes are stamped on every drum, jerrican, box, bag, and IBC approved for hazardous goods. The code names what the packaging is approved to carry; mismatches between cargo and packaging are a customs and carrier hold trigger.

Read the code straight off the stamp moulded into the drum or IBC, never a label or sticker. Type it with or without the UN prefix; the decoder strips it.

Common codes

1A1 Closed top, non-removable head steel drum (typical 200 L liquid drum)
1A2 Open top, removable head steel drum
1H1 Closed top plastic (HDPE) drum
1H2 Open top plastic drum
3H1 Closed top plastic jerrican (typical 25 L)
4G Fibreboard box (cardboard carton)
4H2 Solid plastic box
5H4 Plastic film bag
5M2 Multi-wall paper bag, water-resistant
6HA1 IBC, plastic inner with steel outer

Reference tables

Kind codes (first digit)

1Drum
2Wooden barrel
3Jerrican
4Box
5Bag
6Composite packaging
7Pressure receptacle

Material codes (letter)

ASteel
BAluminium
CNatural wood
DPlywood
FReconstituted wood
GFibreboard
HPlastics
LTextile
MMulti-wall paper
NMetal (other than steel/aluminium)
PGlass / ceramic / pottery

General guidance only. Verify against the cited primary sources before you commit to a shipment, declaration, or contract.

UN packaging marks tie cargo to container

UN-rated packaging is the regulator approval that a drum, jerrican, box, bag, or IBC can carry hazardous cargo of a specified Packing Group. The mark is stamped or moulded into the packaging itself; it is never on a label or sticker. The carrier and customs verify by reading the stamp directly. Without the right UN mark, hazmat cargo cannot ship; the carrier offloads at origin or the cargo is held at destination customs.

The full mark is dense. UN 1A1/Y1.4/100/24/USA/M5678 reads: UN preamble; 1A1 = closed-top steel drum; Y = approved for Packing Group II and III; 1.4 = max cargo specific gravity; 100 = hydraulic test pressure 100 kPa; 24 = manufactured 2024; USA = country of approval (or a country code); M5678 = manufacturer reference. Each token is verified against the cargo SDS before loading.

Packing Group is the cargo-side input. Most chemical hazmat falls into Class 3 (flammable liquids), Class 4 (flammable solids), Class 6.1 (toxic), or Class 8 (corrosive). Each class subdivides into Packing Groups: PG I high danger, PG II medium, PG III low. The packaging X/Y/Z must equal or exceed the cargo PG: PG I needs X; PG II needs X or Y; PG III accepts X, Y, or Z.

For chemical liquid cargo at a specific gravity above the drum-marked limit (e.g. sulphuric acid at SG 1.83 in a Y1.4 drum), the packaging fails the carrier check. The buyer side either re-drums into a higher-rated container (X1.9 or Y1.9 typical) or rejects the shipment. Always cross-check the cargo SDS section 9 SG against the drum mark before loading.

A worked example

You have a parcel of sulphuric acid 98% (UN 1830, SG 1.83) and the supplier offers 200 L closed-top steel drums stamped 1A1/Y1.4. The drums are new, certified, and steel, so they look right.

They aren't. The Y1.4 mark caps the cargo at SG 1.4, and sulphuric acid at 1.83 is well past it. The carrier reads the stamp at acceptance and rejects the booking with the cargo already on the dock. The mark is a hard limit, not a guideline.

Re-drum into 1A1/X1.9 steel drums instead. The X rating covers Packing Groups I to III and the 1.9 density limit clears the 1.83 cargo. Same steel drum, correct stamp, and the load ships.

Not sure of the cargo's UN number and Packing Group in the first place? The DG classifier returns the IMDG entry and class at /tools/dg-classifier.

Once the drum is right, work out how many fit the box at /tools/chemicals/drum-ibc-palletising-calculator.

Frequently asked

What does a UN packaging code look like?

Format: number + letter(s) + number. Example 1A1: kind code 1 (drum), material A (steel), category 1 (closed top, non-removable head). Example 4G: kind 4 (box), material G (fibreboard). The full form often includes a packing-group letter (X, Y, or Z) plus the year of manufacture and the test pressure.

What do X, Y, and Z mean on the code?

X = approved for Packing Groups I, II, III (most hazardous, plus medium and low). Y = approved for Packing Groups II and III only. Z = approved for Packing Group III only (least hazardous). The marking must match the cargo Packing Group.

How do I read 1A1/Y1.4/100/24/USA/M5678?

1A1 = closed-top steel drum; Y = approved for PG II and III; 1.4 = relative density limit 1.4 (cargo with SG above 1.4 cannot use this drum); 100 = hydraulic test pressure 100 kPa; 24 = manufactured in 2024; USA = country of approval; M5678 = manufacturer mark. The full string is the legal stamp on the drum.

When is the year of manufacture mark important?

Per UN Model Regulations 4.1.1.15, PLASTIC drums, jerricans, and rigid-plastic IBCs (and composite IBCs with plastic inner) have a 5-year limit from date of manufacture. STEEL and other metal packagings are NOT subject to a strict 5-year rule; they are inspection-based reuse per the carrier and regulator. A plastic drum manufactured in 2020 cannot ship liquid hazmat in 2026 even if it looks pristine. Customs and carrier inspectors check the year-of-manufacture mark.

Related tools