Guidance document on how to generate an IBAN from an existing
Irish National Sort Code and account number
1. The National Sort Code and account number must be modulus checked (Mod 10 & 11) as per
the IPSO Modulus Checking Standard available from IPSO.
Note: The following sort-code should not be Mod 11 checked: 90-13-94
2. Check that the National Sort Code is reachable for SEPA.
a. Log-on to the IPSO website and register to download from National Sort Code
Database via this link – click here
Once registered you can sign-in here
b. Download the SEPA Reachable Database in (XML, CSV or PDF) format.
3. Construct the IBAN (ISO Standard 13616-1 2007) using Modulus 97 as follows using 00 in
place of the check digit.
NSC:
92-05-01
Account Number:
12345678
Country Code:
IE
BIC:
IRCEIE2DAPS (Available from IPSO National Sort Code Database)
The mock IBAN would be: IE00IRCE92050112345678
Representing:
[Country Code][2 digit check digit][4 digit bank reference – first 4 characters of BIC
code][NSC – with separators removed][Account number]
Move the Country Code, in this case IE, and the digits 00 to the end of the IBAN as follows:
IRCE92050112345678IE00
Calculating the IBAN
In order to calculate the check digits, the characters are temporarily replaced by numbers
according to the following table.
A
B
C
D
E
10
11
12
13
14
F
G
H
I
J
15
16
17
18
19
K
L
M
N
O
20
21
22
23
24
P
Q
R
S
T
25
26
27
28
29
U
V
W
X
Y
Z
30
31
32
33
34
35
The number would now look like
1827121492050112345678181400
Calculate the Mod 97 on the number and subtract the remainder from 98. If the result is a
single digit then insert a leading 0 (zero). The remainder in this example is 34, therefore the
check digits are 98 – 34 = 64 so IBAN = IE64IRCE92050112345678 based on following
calculation:
The process for calculating an IBAN using Mod-97 piece-wise is:
1. Starting from the leftmost digit of the IBAN string being mod-checked (call it D),
construct a number using the first 9 digits and call it N.
2. Calculate N mod 97 by dividing N by 97 and multiplying the 1st 3 digits of the remainder
by 97, round this number to the closest whole number.
3. Construct a new 9 digit N from the above result (step 2) followed by the next 7 digits of
the IBAN string. If there are fewer than 7 digits remaining in D but at least one, then
construct a new N, which will have less than 9 digits, from the above result (step 2)
followed by the remaining digits of D.
4. Repeat steps 2–3 until all the digits of D have been processed.
The result of the final calculation will provide the check digit.
STEP 1
N = 182712149
STEP 2
Divide N by 97
182712149/ 97 =1883630.402
Take the remainder (.402) and multiply by 97
0.402*97=38.994 Rounded to 39
STEP 3
Construct the next 9 digits from the remainder (39 above) followed by the next 7 or 8 digits
of the number depending whether the remainder was one or two digits.
Divide this set of 9 digits by 97
392050112/ 97 =4041753.732
Take the remainder (.732) and multiply by 97
0.732 * 97 = 71.004 rounded to 71
STEP 4
Construct the next 9 digits from the remainder (71) followed by the next 7 or 8 digits of the
number depending whether the remainder was one or two digits.
Divide this set of 9 digits by 97
713456781/ 97 = 7355224.546
Take the remainder (.546) and multiply by 97
0.546 * 97 = 52.962 Rounded to 53
STEP 5
Construct the next number using the remainder (53) followed by the remaining digits.
Divide this number by 97
5381400 / 97 = 55478.35052
Take the remainder (.350) and multiply by 97
0.350 * 97 = 33.95 Rounded to 34
Subtract 34 from 98 = 64 which is Check Digit and the correct IBAN is
Country
Code
Check
Digits
Bank
Code
Sort Code & Account
Number
IE
64
IRCE
92050112345678
IBAN Standard – ISO 13616-1:2007
Please note that the ISO standard for the IBAN (ISO13616) defines the structure and format of the
international identifier for bank accounts. Copies of the standard can be purchased through ISO at
www.iso.org