Isolate scheme-specific check characters.
Initialising algorithm engine for Check Digit Extraction Tool...
How Check Digit Extraction Tool Works?
The Check Digit Extraction Tool separates check characters from the rest of a code. It uses the check positions defined by the scheme. Those positions may be at the end, in the middle or in 2–5 places.
- 1Paste the identifier.
- 2Select the scheme so the tool knows the check positions.
- 3Normalise separators and case.
- 4Copy the characters at the check positions into the output.
- 5Return the payload with the check characters removed.
Check Digit Extraction Tool Formula
The extraction formula is Check = identifier[P_scheme] and Payload = identifier without P_scheme.
P_scheme = set of check positions Check = [identifier[p] for p in P_scheme] Payload = identifier with positions in P_scheme removed
P_schemeis the list of check positions.
Check position = 9 Check = X Payload = 1M8GDM9A + KP042788
Check Digit Extraction Tool Conversion Table
The extraction table lists where 8 schemes store their check characters.
| Scheme | Identifier | Check positions | Extracted check | Payload |
|---|---|---|---|---|
| EAN-13 | 5901234123457 | Position 13 | 7 | 590123412345 |
| IBAN | GB82WEST12345698765432 | Positions 3–4 | 82 | GB WEST12345698765432 |
| VIN | 1M8GDM9AXKP042788 | Position 9 | X | 1M8GDM9A KP042788 |
| ISBN-10 | 0306406152 | Position 10 | 2 | 030640615 |
| Passport MRZ | L898902C36UTO7408122F1204159ZE184226B<<<<<10 | Positions 10, 20, 28, 43, 44 | 6, 2, 9, 1, 0 | Fields without check digits |
| ISAN | 0000-0000-3A8D-0000-Z-0000-0000-6 | After episode and after version | Z, 6 | 000000003A8D0000 + 00000000 |
| CPF | 11144477735 | Positions 10–11 | 35 | 111444777 |
| GMN | 1987654Ad4X4bL5ttr2310c2K | Last 2 characters | 2K | 1987654Ad4X4bL5ttr2310c |
What is Check Digit Extraction Tool?
A Check Digit Extraction Tool is a tool that isolates the check characters of an identifier by the scheme's layout. The output feeds validation, analysis, and database columns.
Extraction is not always the last character: VINs use position 9, IBANs use positions 3–4, and passports carry 5 check digits in 1 line.
What are the uses of Check Digit Extraction Tool?
There are 3 main uses of the Check Digit Extraction Tool, including database design, parser testing, and data analysis.
- Database design: Architects store payload and check fields in separate columns.
- Parser testing: Developers confirm parsers split fields correctly.
- Data analysis: Analysts count check value distributions across a dataset.