how many possible ss#'s are there? my boss says 999999999 and would love to prove him wrong?

Question

trying to figure out how many possible combinations there are for social security numbers???? Please Help!!!!

Answer 1

It depends on what you and your boss mean by 'possible' SSNs. If you mean how many combinations of the form nnn-nn-nnnn where n can be any digit (0-9) then mathematics tells us there would be 10 choices for the first digit times 10 choices for the second times 10 choices for the third... for a total of 9 digits. This is 10^9 combinations (or 1 billion)

Without excluding 000-00-0000, your boss (with a number of 999,999,999) is one short of the theoretical maximum in terms of combinations and would therefore be incorrect.

Now if he wants to say, 'well 000-00-0000 isn't allowed, that's why I said 999,999,999 combinations' you can tell him the following:

Currently, a valid SSN cannot have the first three digits (the area number) above 772, the highest area number which the Social Security Administration has allocated.

There are also special numbers which will never be allocated such as:
Numbers with all zeros in a digit group (000-xx-xxxx, xxx-00-xxxx, xxx-xx-0000).
Numbers of the form 666-xx-xxxx, probably due to the potential controversy. Though the omission of this area number is not acknowledged by the SSA, it remains unassigned.
Numbers from 987-65-4320 to 987-65-4329 are reserved for advertising use. In addition, numbers outside this range, that were used in advertising or otherwise became published can be 'retired' too.

So with all these restrictions, in actuality it's not just 000-00-0000 that is invalid. *Many* of these 1 billion (or 999,999,999) combinations are impossible. Thus your boss would still be wrong!

It's always nice to help someone prove their boss is wrong, one way or another. :)

Answer 2

Hmm.. quite a number of different kinds of answers.
Let's look at it this way. You have 10 digits, 0-9 and there are 9 placeholders. you can put any digit in any placeholder and repeat any digit any number of times, right? That means it doesn't matter what number you choose in the first place to decide what # you put in the second, that is the choices for each is independent.
So you can choose the first digit in 10 ways (anyone from 0-9)
for each choice of the first digit you can choose the second digit in 10 ways too (0-9) e.g. if you choose the first one as 0, the two digits can be 00,01,02,03.... 09.
If you choose the first one as 1, then you will get 10,11,12,...19
And so on...
so for just two places you have 10x10 ways of arranging the digits. Which is 10^2.
So you can go on this way and since there are 9 positions you can arrange the digits in 10^9 ways which is 1 billion. However, there are certain #s which are possibly left out like 000-00-0000 or 999-99-9999..
It may be safe to assume that any # with a lot of repetitions of the same digit is left out, like 111-11-1111, or 222-22-2222 etc.. or even 111-11-0000.. those are very easy to duplicate.
But theoretically your boss is pretty close, he is just 1 short. From a practical point of view he may be over-estimating, as I pointed out some numbers will be left out and there are actually less than 1 billion.
hope this helps.

Answer 3

The number 078-05-1120 has been invalidated by the administration, since it was used in public advertising. So there is at least one less than 999999999! There....your boss is wrong!

Answer 4

There are less than you think for ssns, some people have even been given the same ssn as another person.

The reason is that the ssn number has meaning. For example: The first 3 digits are the location you are from.

Answer 5

If all SSI# are nine digits then, yes, there are 999,999,999 combos. If you count 000-00-0000 then there are 1,000,000,000 combos. I don't know that there are 1 million in use though. Consider also that some may invalid. The fact is there are indeed 1 million possible combos.

Answer 6

Well there are nine numbers in a social security number right? So:
The odds of getting first number is 90(9x10)
Then you'd do something like 90 to the power of nine.Someone fetch a calculator....

Answer 7

Much much more than 999999999 because SS#'s do not have to be in 123-45-6789 order

the actual number is: 4261625379

Answer 8

If you start at zero and count all the way up to 999,999,999, you'll hit every single social security number that there is, from 00-000-0000 to 99-999-9999.

Answer 9

sorry guys, but the government does not allow ss numbers that start with 000, or 001 or many other combinations. so the number of possible ss numbers is closer to 950,000,000. when people die, after so many years, those numbers get recycled

Answer 10

1,000,000,000

But there are numbers that will not be used by the Government. One billion is the theoretical total. (44 as the 2 digit entry is invalid...)