It was back in 1999 that many articles were written predicting that the United States would run out of phone numbers, driven by the then fresh surge of cell phones, fax machines, and virtual numbers.  The solution at the time was area code splits and overlays, but neither was very popular. And, it wasn’t that we were really running out of individual numbers.  After all, 10 digits yields some 10 billion unique combinations. Even allowing for reserved combinations (411, 911, 555, etc.) there’s still plenty of combinations. Today, there are about 900 million active phone lines. A phone company would request an NPA-NXX, which equated to the block of 10,000 numbers following the first 6 (e.g. 813-984-0001 to 9999). But so many new VOIP, cable, skype-like companies were requesting blocks that the country was running out of blocks to give out. The solution was number portability. Any number could move to any service provider (fixed, wireless, VOIP, virtual).

Are we running out of credit card numbers?

Fast forward to 2016, and there are predictions that we will run out of credit card numbers. However, just like phone numbers, it’s not the case where we are exhausting every single combination of the standard 16 digit number found on every credit, debit, prepaid, card and some gift cards, airline cards and gas cards. That would be 1 quadrillion unique numbers worldwide (the 16th digit is a checksum).

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