Container Size and Type Codes (22G1, 45G1, 45R1)

Size code

The first character gives the length (2 = 20 ft, 4 = 40 ft, L = 45 ft) and the second gives height (for example 2 = 8 ft 6 in, 5 = 9 ft 6 in high cube).

Extracting It Automatically

When you read this data from photos, the Container Number OCR API returns it as structured JSON, and you can apply the rules on this page as validation. Try it with the free scanner.

Where This Fits

• Type code: The last two characters give the type: G for general purpose, R for reefer, U for open top, P for platform and flat rack, T for tank, followed by a detail digit.
• Common examples: 22G1 is a 20 ft standard dry container, 42G1 a 40 ft standard, 45G1 a 40 ft high cube, and 45R1 a 40 ft high-cube reefer.

Extract It with the API

Read the document from a photo and validate the returned fields.

Prerequisite: Python 3.9+, `pip install requests`, and a STRUCTOCR_API_KEY

import base64
import os
import requests

with open("container.jpg", "rb") as image_file:
    image = base64.b64encode(image_file.read()).decode("ascii")

response = requests.post(
    "https://api.structocr.com/v1/container",
    headers={"x-api-key": os.environ["STRUCTOCR_API_KEY"]},
    json={"img": image},
    timeout=30,
)
response.raise_for_status()
data = response.json()["data"]
print("container_number:", data.get("container_number"))
print("is_valid:", data.get("is_valid"))
print("confidence:", data.get("confidence"))

Reference Summary

Key facts from this page in structured form, for quick lookup.

{
  "Size code": "The first character gives the length (2 = 20 ft, 4 = 40 ft, L = 45 ft) and the second gives height (for example 2 = 8 ft 6 in, 5 = 9 ft 6 in high cube)..",
  "Type code": "The last two characters give the type: G for general purpose, R for reefer, U for open top, P for platform and flat rack, T for tank, followed by a detail digit..",
  "Common examples": "22G1 is a 20 ft standard dry container, 42G1 a 40 ft standard, 45G1 a 40 ft high cube, and 45R1 a 40 ft high-cube reefer.."
}