Container Number and CSC Nameplate Interpretation: Meaning of Owner Code, Size Code, and Safety Approval Plate

Every container has a unique "ID number" — the container number — and a CSC nameplate that displays safety information. Understanding them is a fundamental skill in container operations.

I. Container Number Format

Container numbers are defined by the ISO 6346:2022 standard, consisting of 11 characters divided into three parts:

Example Container Number: MSCU 123456 7

           │││││ ││││││ │
           │││││ ││││││ └─ ⑧ Check Digit
           │││││ └──┴──┴──┴──┴── ⑥-⑦ Serial Number (6 digits)
           └┴┴┴┴─ ①-④ Owner Code (4 letters)
                    ⑤ Equipment Category Identifier (1 letter: U = General Container, J = Equipment, Z = Trailer)

Explanation of Each Part

Common Owner Codes

Owner Code Registration: All owner codes are managed and registered by the Bureau International des Containers (BIC), with an annual fee required. Owner codes registered in China must be applied for through the BIC official website.

Container Type Code (Not Part of the Container Number)

The container number does not include container type information. Another marking on the container body is the ISO Size/Type Code, typically displayed together with the container number:

II. Check Digit Calculation

The check digit is used to verify whether the container number is correct. The calculation method is as follows:

Calculation Steps:

1. Convert letters to numbers according to the conversion table
2. Multiply each digit by the corresponding power-of-2 weight
3. Divide the sum by 11; the remainder is the check digit

Letter-to-Number Conversion Table

Note: The conversion table does not include the digits 0 and 11. This is to distinguish the letter O from the digit 0, and to avoid the check digit being 11 (a two-digit check digit is impossible, so letter-number equivalents above 10 are skipped accordingly).

Calculation Example

Container Number: MSCU 123456 → What is the check digit?

Step 1: Convert letters to numbers M=24, S=30, C=13, U=32, 1=1, 2=2, 3=3, 4=4, 5=5, 6=6

Step 2: Multiply by weights (from 2⁰ to 2⁹)

24×1  +  30×2  +  13×4  +  32×8  +  1×16  +  2×32  +  3×64  +  4×128  +  5×256  +  6×512
 =24  +  60   +  52    +  256   +  16    +  64    +  192   +   512   +  1,280  +  3,072
 = 5,528

Step 3: Divide by 11 and take the remainder 5,528 ÷ 11 = 502 remainder 6

Check Digit = 6 ✓

Verification Tool: Systems at most shipping lines and terminals automatically verify the check digit when entering container numbers. If the check digit is incorrect, the system will report an error, prompting a check for input mistakes in the container number.

III. CSC Safety Approval Plate

The CSC Nameplate (CSC Safety Approval Plate) is a mandatory certification marking for containers used in international transport, permanently fixed in a clearly visible position on the container door.

Detailed Explanation of Nameplate Fields

┌──────────────────────────────────────────────┐
│        CSC SAFETY APPROVAL                     │
│        CN/CCS/00123/2026                       │ ← Approval Country/Authority/Approval No./Year
│                                                │
│        DATE MANUFACTURED : 2026-03            │ ← Date of Manufacture
│        IDENTIFICATION NO. : MSCU1234567       │ ← Container Number
│        MAXIMUM GROSS WEIGHT : 30,480 KG       │ ← Max Gross Weight (container + cargo)
│                               67,200 LB       │ ← Imperial unit
│        ALLOWABLE STACKING WEIGHT : 192,000 KG │ ← Allowable Stacking Weight (MGW × 1.8)
│                                  423,280 LB   │
│        RACKING TEST LOAD : 15,240 KG          │ ← Transverse Racking Test Load
│                              33,600 LB        │
│                                                │
│        ┌─── EXAMINATION SCHEDULE ───┐          │
│        │  PES : 2031-03 (1st)       │          │ ← Next Periodic Examination Date
│        │  ACEP: 2028-09             │          │ ← ACEP Expiry Date
│        └──────────────────────────────┘          │
└──────────────────────────────────────────────┘

Nameplate Updates for Each Examination Regime

IV. Other Markings

4.1 Country Codes

4.2 Maximum Gross Weight Markings

The following markings are typically also found on the container body:

• MGW (Max Gross Weight): Maximum gross weight (container + cargo)
• TARE: Tare weight of the container body
• NET: Maximum payload (NET = MGW - TARE)

4.3 International Union of Railways Marking (RIV/UIC)

Containers used for railway transport require the RIV marking, indicating compliance with International Union of Railways standards.

4.4 High Cube Warning Marking

High cube containers such as 40HQ and 45HQ (container height >2.591m) must have a yellow/black high cube warning marking on both sides of the container body and above the container doors, reminding personnel to be aware of height restrictions.

Data Note: Container number format references the ISO 6346:2022 standard. CSC nameplate fields reference the CSC Convention and China Classification Society (CCS) inspection regulations. Data as of July 2026.

Need to verify a container number or check a CSC nameplate? Send us a photo, and we will verify whether the inspection date is valid for free.

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