Luhn algorithm: Difference between revisions

Revision as of 11:43, 31 August 2023

Revision as of 12:35, 31 August 2023

Line 31:

|-

! Multipliers

| 2

| 1

| 2

Line 41 ⟶ 40:

| 2

| 1

| 2

|-

!

Line 55:

|-

!

|9 7

| '''14'''

| style="background: #FFA;" | 9'''18'''

|5 9

| '''18'''

| style="background: #FFA;" | 2'''4'''

|9 7

| '''14'''

| style="background: #FFA;" | 3'''6'''

|5 9

| '''18'''

| style="background: #FFA;" | 8'''16'''

| 7

| '''14'''

| style="background: #FFA;" | 1'''2'''

|-

! Sum digits

|5 7

| '''189''' (1+8)

|39

| '''144'''

|87

| '''186'''

|9

| '''147''' (1+6)

|9

|27

| '''142'''

|5

|3

|9

|8

|5

|1

|}

The sum of the resulting digits is 5667.

The check digit is equal to <math>10 - (5667\operatorname{mod} 10) = 43</math>.

This makes the full account number read 7992739871479927398713.

=== Example for validating check digit ===

# Drop the check digit (last digit) of the number to validate. (e.g. 7992739871479927398713 -> 7992739871)

# Calculate the check digit (see above)

# Compare your result with the original check digit. If both numbers match, the result is valid. (e.g.<math>(givenCheckDigit = calculatedCheckDigit) \Leftrightarrow (isValidCheckDigit)</math>).