# IBAN Validation check

Hi there i need to do an IBAN validation check using `javascript`.

The rules i need to follow are

Validating the IBAN An IBAN is validated by converting it into an integer and performing a basic mod-97 operation (as described in ISO 7064) on it. If the IBAN is valid, the remainder equals 1.

1.Check that the total IBAN length is correct as per the country. If not, the IBAN is invalid

2.Move the four initial characters to the end of the string

3.Replace each letter in the string with two digits, thereby expanding the string, where A = 10, B = 11, ..., Z = 35

4.Interpret the string as a decimal integer and compute the remainder of that number on division by 97

I am doing this for a Belarusian IBAN so it has to follow the following format

2C 31N -

RU1230000000000000000000000000000

How do i modify the following to meet the above rules;

``````function validateIBAN(iban) {
var newIban = iban.toUpperCase(),
modulo = function (divident, divisor) {
var cDivident = '';
var cRest = '';

for (var i in divident ) {
var cChar = divident[i];
var cOperator = cRest + '' + cDivident + '' + cChar;

if ( cOperator < parseInt(divisor) ) {
cDivident += '' + cChar;
} else {
cRest = cOperator % divisor;
if ( cRest == 0 ) {
cRest = '';
}
cDivident = '';
}

}
cRest += '' + cDivident;
if (cRest == '') {
cRest = 0;
}
return cRest;
};

if (newIban.search(/^[A-Z]{2}/gi) < 0) {
return false;
}

newIban = newIban.substring(4) + newIban.substring(0, 4);

newIban = newIban.replace(/[A-Z]/g, function (match) {
return match.charCodeAt(0) - 55;
});

return parseInt(modulo(newIban, 97), 10) === 1;
}
``````

You can use this library to validate and format an IBAN: https://github.com/arhs/iban.js (disclaimer: I wrote the library)

However, neither Russia nor Belarus are supported, as I can't find any mention of those countries on the IBAN page of wikipedia nor in the official IBAN registry so I'm afraid you'll have to modify the library code yourself to add it.

Based on the work of http://toms-cafe.de/iban/iban.js I have developed my version of IBAN check.

You can modify the country support by modifying the variable CODE_LENGTHS

Here is my implementation:

``````function alertValidIBAN(iban) {
}
/*
* Returns 1 if the IBAN is valid
* Returns FALSE if the IBAN's length is not as should be (for CY the IBAN Should be 28 chars long starting with CY )
* Returns any other number (checksum) when the IBAN is invalid (check digits do not match)
*/
function isValidIBANNumber(input) {
var CODE_LENGTHS = {
AD: 24, AE: 23, AT: 20, AZ: 28, BA: 20, BE: 16, BG: 22, BH: 22, BR: 29,
CH: 21, CR: 21, CY: 28, CZ: 24, DE: 22, DK: 18, DO: 28, EE: 20, ES: 24,
FI: 18, FO: 18, FR: 27, GB: 22, GI: 23, GL: 18, GR: 27, GT: 28, HR: 21,
HU: 28, IE: 22, IL: 23, IS: 26, IT: 27, JO: 30, KW: 30, KZ: 20, LB: 28,
LI: 21, LT: 20, LU: 20, LV: 21, MC: 27, MD: 24, ME: 22, MK: 19, MR: 27,
MT: 31, MU: 30, NL: 18, NO: 15, PK: 24, PL: 28, PS: 29, PT: 25, QA: 29,
RO: 24, RS: 22, SA: 24, SE: 24, SI: 19, SK: 24, SM: 27, TN: 24, TR: 26
};
var iban = String(input).toUpperCase().replace(/[^A-Z0-9]/g, ''), // keep only alphanumeric characters
code = iban.match(/^([A-Z]{2})(\d{2})([A-Z\d]+)\$/), // match and capture (1) the country code, (2) the check digits, and (3) the rest
digits;
// check syntax and length
if (!code || iban.length !== CODE_LENGTHS[code[1]]) {
return false;
}
// rearrange country code and check digits, and convert chars to ints
digits = (code[3] + code[1] + code[2]).replace(/[A-Z]/g, function (letter) {
return letter.charCodeAt(0) - 55;
});
// final check
return mod97(digits);
}
function mod97(string) {
var checksum = string.slice(0, 2), fragment;
for (var offset = 2; offset < string.length; offset += 7) {
fragment = String(checksum) + string.substring(offset, offset + 7);
checksum = parseInt(fragment, 10) % 97;
}
return checksum;
}
``````

Here is also a working fiddle

"Jquery validation plugin" also supports iban check:

Based on previous answers I created a `Directive` that implements Angular `Validator` method.

iban-validator.directive.ts

``````import { Validator, AbstractControl, NG_VALIDATORS } from '@angular/forms';
import { Directive } from '@angular/core';

@Directive({
selector: '[ibanValidators]',
providers: [{
provide: NG_VALIDATORS,
useExisting: IbanValidatorDirective,
multi: true
}]
})

export class IbanValidatorDirective implements Validator {

validate(control: AbstractControl): object {
const codeLengths = {
AD: 24, AE: 23, AL: 28, AT: 20, AZ: 28, BA: 20, BE: 16, BG: 22, BH: 22, BR: 29, CH: 21, CR: 21, CY: 28, CZ: 24,
DE: 22, DK: 18, DO: 28, EE: 20, ES: 24, LC: 30, FI: 18, FO: 18, FR: 27, GB: 22, GI: 23, GL: 18, GR: 27, GT: 28,
HR: 21, HU: 28, IE: 22, IL: 23, IS: 26, IT: 27, JO: 30, KW: 30, KZ: 20, LB: 28, LI: 21, LT: 20, LU: 20, LV: 21,
MC: 27, MD: 24, ME: 22, MK: 19, MR: 27, MT: 31, MU: 30, NL: 18, NO: 15, PK: 24, PL: 28, PS: 29, PT: 25, QA: 29,
RO: 24, RS: 22, SA: 24, SE: 24, SI: 19, SK: 24, SM: 27, TN: 24, TR: 26
};
if (control.value) {
const iban = control.value.toUpperCase().replace(/[^A-Z0-9]/g, '');
const code = iban.match(/^([A-Z]{2})(\d{2})([A-Z\d]+)\$/);
let digits: number;
if (!code || iban.length !== codeLengths[code[1]]) {
return { ibanValid: false };
}
digits = (code[3] + code[1] + code[2]).replace(/[A-Z]/g, (letter: string) => {
return letter.charCodeAt(0) - 55;
});
return this.mod97(digits) === 1 ? null : { ibanValid: false };
}
}

private mod97(digital: number | string) {
digital = digital.toString();
let checksum: number | string = digital.slice(0, 2);
let fragment = '';
for (let offset = 2; offset < digital.length; offset += 7) {
fragment = checksum + digital.substring(offset, offset + 7);
checksum = parseInt(fragment, 10) % 97;
}
return checksum;
}
}
``````

Then just use the directive on an input.

I answered a similar question. Use this list of Regular expressions to validate your IBANS. There are 70 countries, so in general you should be good to go.

``````AL[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){2}([a-zA-Z0-9]{4}\s?){4}\s?
AT[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}\s?
AZ[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{4}\s?){1}([0-9]{4}\s?){5}\s?
BH[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([a-zA-Z0-9]{4}\s?){3}([a-zA-Z0-9]{2})\s?
BY[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{4}\s?){1}([0-9]{4}\s?){5}\s?
BE[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){3}\s?
BA[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}\s?
BR[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}([0-9]{3})([a-zA-Z]{1}\s?)([a-zA-Z0-9]{1})\s?
BG[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([0-9]{4}\s?){1}([0-9]{2})([a-zA-Z0-9]{2}\s?)([a-zA-Z0-9]{4}\s?){1}([a-zA-Z0-9]{2})\s?
CR[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}([0-9]{2})\s?
HR[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}([0-9]{1})\s?
CY[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){2}([a-zA-Z0-9]{4}\s?){4}\s?
CZ[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}\s?
DK[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){3}([0-9]{2})\s?
DO[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([0-9]{4}\s?){5}\s?
TL[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}([0-9]{3})\s?
EE[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}\s?
FO[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){3}([0-9]{2})\s?
FI[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){3}([0-9]{2})\s?
FR[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){2}([0-9]{2})([a-zA-Z0-9]{2}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{1})([0-9]{2})\s?
GE[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{2})([0-9]{2}\s?)([0-9]{4}\s?){3}([0-9]{2})\s?
DE[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}([0-9]{2})\s?
GI[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([a-zA-Z0-9]{4}\s?){3}([a-zA-Z0-9]{3})\s?
GR[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){1}([0-9]{3})([a-zA-Z0-9]{1}\s?)([a-zA-Z0-9]{4}\s?){3}([a-zA-Z0-9]{3})\s?
GL[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){3}([0-9]{2})\s?
GT[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{4}\s?){1}([a-zA-Z0-9]{4}\s?){5}\s?
HU[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){6}\s?
IS[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}([0-9]{2})\s?
IE[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{4}\s?){1}([0-9]{4}\s?){3}([0-9]{2})\s?
IL[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}([0-9]{3})\s?
IT[a-zA-Z0-9]{2}\s?([a-zA-Z]{1})([0-9]{3}\s?)([0-9]{4}\s?){1}([0-9]{3})([a-zA-Z0-9]{1}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{3})\s?
JO[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([0-9]{4}\s?){5}([0-9]{2})\s?
KZ[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){3}([0-9]{1})([a-zA-Z0-9]{3}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{2})\s?
XK[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){1}([0-9]{4}\s?){2}([0-9]{2})([0-9]{2}\s?)\s?
KW[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([a-zA-Z0-9]{4}\s?){5}([a-zA-Z0-9]{2})\s?
LV[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([a-zA-Z0-9]{4}\s?){3}([a-zA-Z0-9]{1})\s?
LB[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){1}([a-zA-Z0-9]{4}\s?){5}\s?
LI[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){1}([0-9]{1})([a-zA-Z0-9]{3}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{1})\s?
LT[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}\s?
LU[a-zA-Z0-9]{2}\s?([0-9]{3})([a-zA-Z0-9]{1}\s?)([a-zA-Z0-9]{4}\s?){3}\s?
MK[a-zA-Z0-9]{2}\s?([0-9]{3})([a-zA-Z0-9]{1}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{1})([0-9]{2})\s?
MT[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([0-9]{4}\s?){1}([0-9]{1})([a-zA-Z0-9]{3}\s?)([a-zA-Z0-9]{4}\s?){3}([a-zA-Z0-9]{3})\s?
MR[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}([0-9]{3})\s?
MU[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([0-9]{4}\s?){4}([0-9]{3})([a-zA-Z]{1}\s?)([a-zA-Z]{2})\s?
MC[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){2}([0-9]{2})([a-zA-Z0-9]{2}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{1})([0-9]{2})\s?
MD[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{2})([a-zA-Z0-9]{2}\s?)([a-zA-Z0-9]{4}\s?){4}\s?
ME[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}([0-9]{2})\s?
NL[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([0-9]{4}\s?){2}([0-9]{2})\s?
NO[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){2}([0-9]{3})\s?
PK[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{4}\s?){1}([0-9]{4}\s?){4}\s?
PS[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{4}\s?){1}([0-9]{4}\s?){5}([0-9]{1})\s?
PL[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){6}\s?
PT[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}([0-9]{1})\s?
QA[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([a-zA-Z0-9]{4}\s?){5}([a-zA-Z0-9]{1})\s?
RO[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([a-zA-Z0-9]{4}\s?){4}\s?
SM[a-zA-Z0-9]{2}\s?([a-zA-Z]{1})([0-9]{3}\s?)([0-9]{4}\s?){1}([0-9]{3})([a-zA-Z0-9]{1}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{3})\s?
SA[a-zA-Z0-9]{2}\s?([0-9]{2})([a-zA-Z0-9]{2}\s?)([a-zA-Z0-9]{4}\s?){4}\s?
RS[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){4}([0-9]{2})\s?
SK[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}\s?
SI[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){3}([0-9]{3})\s?
ES[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}\s?
SE[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}\s?
CH[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){1}([0-9]{1})([a-zA-Z0-9]{3}\s?)([a-zA-Z0-9]{4}\s?){2}([a-zA-Z0-9]{1})\s?
TN[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){5}\s?
TR[a-zA-Z0-9]{2}\s?([0-9]{4}\s?){1}([0-9]{1})([a-zA-Z0-9]{3}\s?)([a-zA-Z0-9]{4}\s?){3}([a-zA-Z0-9]{2})\s?
AE[a-zA-Z0-9]{2}\s?([0-9]{3})([0-9]{1}\s?)([0-9]{4}\s?){3}([0-9]{3})\s?
GB[a-zA-Z0-9]{2}\s?([a-zA-Z]{4}\s?){1}([0-9]{4}\s?){3}([0-9]{2})\s?
VA[a-zA-Z0-9]{2}\s?([0-9]{3})([0-9]{1}\s?)([0-9]{4}\s?){3}([0-9]{2})\s?
VG[a-zA-Z0-9]{2}\s?([a-zA-Z0-9]{4}\s?){1}([0-9]{4}\s?){4}\s?
``````

I know this is an old topic, but since it showed up on #1 place on Google, and since the solutions here aren't really refined I would like to show you my take on it:

``````export const validIban = (value) => {
let rearrange =
value.substring(4, value.length)
+ value.substring(0, 4);
let alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split('');
let alphaMap = {};
let number = [];

alphabet.forEach((value, index) => {
alphaMap[value] = index + 10;
});

rearrange.split('').forEach((value, index) => {
number[index] = alphaMap[value] || value;
});

return modulo(number.join('').toString(), 97) === 1;
}

const modulo = (aNumStr, aDiv) => {
var tmp = "";
var i, r;
for (i = 0; i < aNumStr.length; i++) {
tmp += aNumStr.charAt(i);
tmp = r.toString();
}
return tmp / 1;
}
``````

It works pretty well for me you can test it with `validIban(testThis)` / http://randomiban.com