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Helper classes to calculate and validate ckecksums

2.1.0 2018-09-29 11:30 UTC

This package is auto-updated.

Last update: 2021-01-03 22:30:27 UTC


ABANDONED! This package is discontinued and will not be updated.


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Helper classes to calculate and validate ckecksums.


composer require byrokrat/checkdigit

Checkdigit requires the bcmath php extension.


The Calculator interface defines two methods:

  • isValid(string $number): bool checks if number contains a valid check digit.
  • calculateCheckDigit(string $number): string calculates the check digit for number.

Implementations include:

  • Modulo10 and Luhn for modulo 10 check digits (Luhn is simply a shorthand for Modulo10).
  • Modulo10Gtin for modulo 10 check digits variant used in GTIN barcodes.
  • Modulo11 for modulo 11 check digits.
  • Modulo97 for modulo 97 check digits.


$luhn = new byrokrat\checkdigit\Luhn;

// outputs '1' (true)
echo $luhn->isValid('55555551');

// outputs '' (false)
echo $luhn->isValid('55555550');

// outputs '1'
echo $luhn->calculateCheckDigit('5555555');