IBAN

IBAN (International Bank Account Number) is the international standard for identifying bank accounts. A Polish IBAN is the two-letter country prefix PL followed by a 26-digit NRB. Validation requires the PL prefix and applies the standard MOD-97 checksum to the NRB portion.

Use Numerik::nrb() when you have a 26-digit number without the country prefix. Use Numerik::iban() when you expect the full international form.

Usage

use SlashLab\Numerik\Numerik;

// Boolean
Numerik::iban()->isValid('PL61102010260000000000000000');   // true

// Spaced format and lowercase prefix are accepted
Numerik::iban()->isValid('PL61 1020 1026 0000 0000 0000 0000');   // true
Numerik::iban()->isValid('pl61102010260000000000000000');          // true

// Bare NRB without prefix is rejected — use Numerik::nrb() for that
Numerik::iban()->isValid('61102010260000000000000000');   // false

// Rich result
$result = Numerik::iban()->validate('PL61102010260000000000000000');
$result->isValid;   // true

// Parse to value object
$iban = Numerik::iban()->parse('PL61102010260000000000000000');

// Null on failure instead of exception
$iban = Numerik::iban()->tryParse('bad-input'); // null

Value object API

parse() and tryParse() return a SlashLab\Numerik\ValueObjects\Iban instance.

Core

Method	Return type	Description
getRaw()	string	The original input, untouched.
getNormalized()	string	PL + 26 digits, e.g. PL61102010260000000000000000.
__toString()	string	Same as getNormalized().

Formatting

Method	Return type	Description
getFormatted()	string	Standard grouped display: PL61 1020 1026 0000 0000 0000 0000.

Structure

Method	Return type	Description
getCountryCode()	string	Always PL.
getNrb()	string	The 26-digit NRB without the country prefix.
getCheckDigits()	string	Two MOD-97 check digits (positions 3–4 of the IBAN).
getSortCode()	string	8-digit bank sort code.
getBankCode()	string	First 3 digits of the sort code — identifies the bank.
getAccountNumber()	string	Last 16 digits — the customer account number.

Examples

$iban = Numerik::iban()->parse('PL61102010260000000000000000');

$iban->getRaw();             // 'PL61102010260000000000000000'
$iban->getNormalized();      // 'PL61102010260000000000000000'
$iban->getFormatted();       // 'PL61 1020 1026 0000 0000 0000 0000'
$iban->getCountryCode();     // 'PL'
$iban->getNrb();             // '61102010260000000000000000'
$iban->getCheckDigits();     // '61'
$iban->getSortCode();        // '10201026'
$iban->getBankCode();        // '102'
$iban->getAccountNumber();   // '0000000000000000'

// Spaced and lowercase inputs normalise to the same value
$a = Numerik::iban()->parse('PL61102010260000000000000000');
$b = Numerik::iban()->parse('PL61 1020 1026 0000 0000 0000 0000');
$c = Numerik::iban()->parse('pl61102010260000000000000000');

$a->getNormalized() === $b->getNormalized(); // true
$b->getNormalized() === $c->getNormalized(); // true

Validation algorithm

1. Strip spaces and hyphens. Reject inputs over 40 characters.
2. Assert the first two characters are PL (case-insensitive); fail with InvalidFormat.
3. Strip the prefix. Assert exactly 26 digits remain; fail with InvalidLength.
4. Apply the NRB MOD-97 checksum — see the Algorithms reference.

Failure reasons

Reason	Value	When
InvalidLength	invalid_length	NRB portion is not exactly 26 digits, or raw input exceeds 40 characters.
InvalidFormat	invalid_format	Input does not start with PL.
InvalidCharacters	invalid_characters	NRB portion contains non-digit characters.
InvalidChecksum	invalid_checksum	MOD-97 remainder is not 1.