import re _country2length = dict( AL=28, AD=24, AT=20, AZ=28, BE=16, BH=22, BA=20, BR=29, BG=22, CR=21, HR=21, CY=28, CZ=24, DK=18, DO=28, EE=20, FO=18, FI=18, FR=27, GE=22, DE=22, GI=23, GR=27, GL=18, GT=28, HU=28, IS=26, IE=22, IL=23, IT=27, KZ=20, KW=30, LV=21, LB=28, LI=21, LT=20, LU=20, MK=19, MT=31, MR=27, MU=30, MC=27, MD=24, ME=22, NL=18, NO=15, PK=24, PS=29, PL=28, PT=25, RO=24, SM=27, SA=24, RS=22, SK=24, SI=19, ES=24, SE=24, CH=21, TN=24, TR=26, AE=23, GB=22, VG=24 ) def valid_iban(iban): # Ensure upper alphanumeric input. iban = iban.replace(' ','').replace('\t','') if not re.match(r'^[\dA-Z]+$', iban): return False # Validate country code against expected length. if len(iban) != _country2length[iban[:2]]: return False # Shift and convert. iban = iban[4:] + iban[:4] digits = int(''.join(str(int(ch, 36)) for ch in iban)) #BASE 36: 0..9,A..Z -> 0..35 return digits % 97 == 1 if __name__ == '__main__': for account in ["GB82 WEST 1234 5698 7654 32", "GB82 TEST 1234 5698 7654 32"]: print('%s validation is: %s' % (account, valid_iban(account)))