How To: Verify BPAY CRN Check Digit (MOD10V01)

This guide helps you test the accuracy of BPAY Customer Reference Number (CRN) generation and validation using the MOD10V01 algorithm via the BPAY CRN Generator Tool.

Overview

You'll complete two tests:

1. Use an existing CRN to extract and validate the check digit.
2. Recreate the CRN using the MOD10V01 rule and compare the results.

This confirms whether the check digit aligns with the expected algorithm.

Step-by-Step Process

Step 1: Extract the Base Number from an Existing CRN

1. Take your full CRN (e.g. 12345678X).
2. Remove the last digit – this is the check digit.
   • Example:
     CRN: 123456789
     Base Number: 12345678
     Check Digit: 9

Step 2: Use the CRN Generator Tool With a Biller Code

1. Go to the BPAY CRN Generator Tool.
2. Select: "I have a BPAY Biller Code"
3. Enter:
   • Your Biller Code
   • The Base Number from Step 1
4. Click Begin to generate the CRN.
5. Comparethe generated CRN to your original CRN:
   • If the check digit matches, it confirms the CRN follows the MOD10V01 algorithm.
   • If not, continue to Step 3 to isolate the algorithm used.

Step 3: Regenerate the CRN Without a Biller Code (MOD10V01 Rule)

1. Return to the CRN Generator Tool.
2. Select: "I don't have a BPAY Biller Code"
3. Choose the MOD10V01 algorithm from the dropdown.
4. Enter the same Base Number from Step 1.
5. Click Begin to generate a CRN.

Step 4: Compare the Results

• If the CRN from Step 2 and Step 3 both return the same check digit, your Biller Code uses the MOD10V01 algorithm.
• If the results differ, your Biller Code likely uses a different check digit rule (e.g. MOD11 or MOD10V05).

Troubleshooting Tips

• No Match? Double-check the base number and that you correctly removed only the final digit.
• Still unsure? Test again with a different CRN from the same Biller Code to see if patterns emerge.
• Unsupported Biller Code? Use Step 3 only with MOD10V01 to isolate consistency.

Example

See Also

• Setting up BPAY