Is your NRIC no. valid?

WARNING: This probably my geekiest post yet (and ever). Heehee.
A colleague recently did a presentation on how to verify if a Singapore NRIC no. is valid. Tot it was interesting and wanted to blog about it but was deliberating on whether it is "Classified" info.. but since I can google it, i guess not. so here goes..

Known by most, the validity of the Singapore NRIC no. is determined by the alphabet right at the end of each NRIC no. But how do we go about checking whether the NRIC no. is correct?

Here's how:


[Source: http://codingncryptography.tripod.com/01NRIC.htm]

For illustration purpose, I will use the NRIC no. S1234567D.


Step 1: Multiply each digit in the NRIC no. by its weight.

Each digit's weight is shown in the table below:
 

Digit’s Position in NRIC no.	1	2	3	4	5	6	7
Weight	2	7	6	5	4	3	2

Thus, multiplying the weights to my sample NRIC no. S1234567D, I get the following:

Digit in our sample NRIC no. [A]	1	2	3	4	5	6	7
Weight [B]	2	7	6	5	4	3	2
[A] x [B]	2	14	18	20	20	18	14

Step 2: Add together the above products.

Sum  = 2 + 14 + 18 + 20 + 20 + 18 + 14 = 106


Step 3: Divide the resulting sum by 11.

Thus, I take 106 and divide it by 11. I get 9 with a remainder of 7. [you need to do this the manual (i.e. pri sch) way, and not with calculator =) ]


Step 4: Take 11 and minus off the remainder. This will give you the check digit.

Check digit = 11 - 7 (remainder) = 4


Step 5: Check the check digit against the table below to get the alphabet.

 

Check Digit	1	2	3	4	5	6	7	8	9	10	11
Alphabet	A	B	C	D	E	F	G	H	I	Z	J

Thus, with my check digit of 4, the alphabet at the end of my sample NRIC would have to be D for it to be valid!

And it is~ so, S1234567D is a valid NRIC! I wonder who it belongs to.. hehee


Quick, go check urs now~ heehee.. and you can use this info to impress your friends by saying you can guess their NRIC alphabet =)

your welcome!