Hull Identification Number (HIN) Format Explained

Twelve characters

A US HIN has 12 characters: a three-character manufacturer identification code (MIC), a five-character serial number, a production month letter and year digit, and the two-digit model year.

Extracting It Automatically

When you read this data from photos, the HIN 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

• Production month: Letters A to L represent January to December, followed by the last digit of the production year.
• Where it is: The primary HIN is on the starboard side of the transom, near the top; a duplicate is placed in an unexposed location on the hull.

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

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

Reference Summary

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

{
  "Twelve characters": "A US HIN has 12 characters: a three-character manufacturer identification code (MIC), a five-character serial number, a production month letter and year digit, and the two-digit model year..",
  "Production month": "Letters A to L represent January to December, followed by the last digit of the production year..",
  "Where it is": "The primary HIN is on the starboard side of the transom, near the top; a duplicate is placed in an unexposed location on the hull.."
}