How do credit card companies not run out of numbers?
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16 digits means you can issue 10,000,000,000,000,000 unique cards, there are only 8,000,000,000 people, so that’s over a million cards per human.
Excluding the first four digits which are unique to each company I think, there are still twelve digits to work with. That’s just shy of a trillion combinations per company. Even if every single person on earth had a unique card number, it would take a very long time to run out of them.
With 16 numbers, that gives them some 10 quadrillion numbers to work with. Even if they decide to remove some gimmicky ones like 00000…, that leaves them with plenty of numbers to go around.
And if that starts to become a problem in the year 2400 when mankind is populating the stars, they can always just add another digit to the next batch.
When there are 16 digits x 10 possibilities for each digit, that’s over a trillion numbers… even with the first number being limited to only 4-5 numbers (it defines what card network, ie .Visa, mastercard, Amex, etc) that’ still many billions of numbers. And they can always re-use numbers after a period of inactivity. New expiration dates and CVV codes would prevent misuse of old, expired numbers.
The long and short is that there is no rule that credit cards have to be 16 digits long. If they actually do start “running out”, they can add more digits.
There are only two or three digits that are actually part of a plan for credit card numbers. The other 13 or 14 can be anything, and that gives 10,000,000,000,000 to 100,000,000,000,000 possible card numbers they can use. Even if they use a couple more digits for extra organizational purposes, they can still have 100 billion possible card numbers, which is more than they will need any time soon.
There’s four groupings of four digits – that’s 9,999,999,999,999,999 possible unique credit card numbers. That’s 91,743 credit cards for every man, woman, and child that has ever lived…in the entire history of human beings.
Even if you factor in that Visa card numbers start with 4, Mastercard starts with 2 or 5, and American Express starts with 3….that’s still a shit-ton of possible numbers for every issuer.
And beyond that if you factor in that the issuing banks have unique numbers for the first 4 to 6 numbers, that still leaves a very high number of cards for the possible number of people that could have one.
Simplest answer? There are more numbers than people
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