Latency: <1ms Edge Availability: 99.99% Standard: ISO 6346 Clause 3 V8 Pure Compute

ISO 6346 Modulo-11 Shipping Container Check Digit Formula & Step-by-Step

Q: What happens if the modulo 11 remainder is 10?

According to ISO 6346, if the remainder is 10, the check digit is designated as 0.

Step-by-step Modulo-11 check digit calculation for 11-character intermodal container numbers.

View Pricing & SLA → ⚡ Test in Live Workbench ← Back to ISO 6346 Container & Chassis Check-Digit Validator API

Official Regulatory Standard & Verification Protocol Authority: Bureau International des Conteneurs (BIC) & ISO ↗

Quick Technical Summary: Step-by-step Modulo-11 check digit calculation for 11-character intermodal container numbers. Implementation conforms to ISO 6346 / BIC Container Prefix Coding.

Execution SLA

<1ms Edge (Cloudflare V8)

Governing Norm

ISO 6346 Clause 3

Throughput Limit

512 KB / Payload

Data Privacy

100% In-Memory (Zero Store)

Specification & Structural Breakdown

The 11th digit is a check digit calculated using powers of 2 weights (2^0 to 2^9) with letters converted to values where multiples of 11 (11, 22, 33) are excluded.

Letters	Assigned Values	Rule
A - J	10, 12, 13, 14, 15, 16, 17, 18, 19, 20	11 is skipped
K - U	21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32	22 is skipped
V - Z	34, 35, 36, 37, 38	33 is skipped

Interactive Edge Validator

Test ISO 6346 Modulo-11 Shipping Container Check Digit Formula & Step-by-Step Live

Paste raw inputs up to 32KB and inspect deterministic parsed JSON in real-time across 330+ Cloudflare edge locations. Pure compute, zero cold-starts.

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Parsed JSON Response Model

The edge microservice transforms input payloads into strongly-typed hierarchical JSON with zero cold starts:

HTTP 200 JSON Payload

{
  "containerNumber": "CSQU3054383",
  "checkDigit": 3,
  "checkDigitCalculated": 3,
  "valid": true
}

Copy-Paste Integration Code

Integrate this validator directly into your application using your production API key:

cURL

curl --request POST \
  --url "https://iso-6346-container-chassis-check-digit-validator.stanzaapi.com/api/v1/container/validate" \
  --header "Content-Type: application/json" \
  --header "x-api-key: YOUR_API_KEY" \
  --data '{
  "containerNumber": "CSQU3054383",
  "sizeTypeCode": "45G1"
}'

Node.js (Fetch)

const response = await fetch("https://iso-6346-container-chassis-check-digit-validator.stanzaapi.com/api/v1/container/validate", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "x-api-key": process.env.API_KEY || "YOUR_API_KEY"
  },
  body: JSON.stringify({
  "containerNumber": "CSQU3054383",
  "sizeTypeCode": "45G1"
})
});

const data = await response.json();
console.log(data);

Python (Requests)

import requests
import json

url = "https://iso-6346-container-chassis-check-digit-validator.stanzaapi.com/api/v1/container/validate"
headers = {
    "Content-Type": "application/json",
    "x-api-key": "YOUR_API_KEY"
}
payload = {
    "containerNumber": "CSQU3054383",
    "sizeTypeCode": "45G1"
}

response = requests.post(url, json=payload, headers=headers)
print(response.json())

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	url := "https://iso-6346-container-chassis-check-digit-validator.stanzaapi.com/api/v1/container/validate"
	payload := []byte(`{"containerNumber":"CSQU3054383","sizeTypeCode":"45G1"}`)

	req, _ := http.NewRequest("POST", url, bytes.NewBuffer(payload))
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("x-api-key", os.Getenv("API_KEY"))

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)
	fmt.Println(string(body))
}

Frequently Asked Questions & Technical Notes

What happens if the modulo 11 remainder is 10?

According to ISO 6346, if the remainder is 10, the check digit is designated as 0.

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