Are there enough credit card numbers?
I was wondering if the 16 digits that most credit cards have (VISA and Mastercard et al) if you don't include American Express' 13 digit cards were enough for the world or if we'd run out of digits at some point.
If I've done my calculations correctly and based on my assumption that there are 7 billion people in the world then there are enough numbers for each person on earth to have just under 1.5 million credit cards.
I then pulled out my wallet and counted that I have 16 credit card sized items in there (some of which are credit cards) and held together they are about 1cm thick. So my next calculation was to see how fat my wallet would have to be to hold 1.5 million credit cards: 937.5 meters wide, that's almost a Km.
Filed under: Algorithms
