# Will There Ever Be An End To 10 Digit Phone Numbers?

Not-so many moons ago in the mid-1990’s, overlay area codes were introduced into the US phone system. Prior to that there was no area code in the United States where the middle digit wasn’t a 0 or a 1. Whenever you see a middle-0 or middle-1 area code these days, those are carryovers from Ye Olde Bell System.

US phone numbers are laid out as area code (3 digit), prefix (3 digit), suffix (4 digit) for a total of 10 digits not including country code (+1). While it may seem we have plenty of phone numbers to go around, we really don’t.

Each suffix can only accommodate for 10,000 assignable numbers (0000 through 9999). And being there are only 1,000 prefixes (000 through 999) per area code, that means that a maximum of 10 million numbers (10,000 assignable numbers x 1,000 prefixes) can be assigned to any one area code. Once the 10 million is expired, another area code must be put in the system to get another 10 million.

### Is the US in danger of one day running out of assignable phone numbers?

There are a total of 1.3 billion assignable phone numbers in the US, and of course the wireless carriers understandably have the lion’s share of them. Back in 2007 it was reported that of the numbers we have, 582 million of them are in use, but then again that’s four-year-old statistics. By now we may have passed the 600 million mark, if not exceeded it.

To answer the question directly, no, we’re not in danger of running out of numbers, however we have well less than 50% of our assignable numbers left.

If you were to look at this from a network address perspective, anything over 40% use isn’t that great of a spot to be in – especially when you have nowhere to go.

### If we ever did hit the limit, what would be the fix?

Were I to guess, a 5-digit suffix, signifying the end of the 10-digit for 11-digit.

The way it would probably work is that if your phone number was 555-123-4567, this would be changed to 555-123-04567. All existing numbers would have a zero added to the front of the suffix to carry them over into the new system. New suffixes on old prefixes would be 10000 through 99999, and new suffixes on new prefixes would be 00000 through 99999..

..unless you can think of a better idea?

## 11 thoughts on “Will There Ever Be An End To 10 Digit Phone Numbers?”

Shields says:
Not only can area codes not start with 0 or 1, but exchanges ALSO can’t start with 0 or 1 because 7 digit dialing is still permitted in the system. In addition, 911, 411, 311, etc can’t be used as exchanges or area codes. 900, 800, 888, 877, etc, are specialty numbers which can’t be assigned to the general public. There are several other restrictions in place, which bring the total down further. The final figure is probably still around 7 billion total, and less that are actually assignable.

But then there’s the most obvious point: The USA is not the only country that uses 1 as its country code. In other words, we share our 10 digit system with several other countries, and those area codes therefore can’t be assigned to Americans. So for example, American Samoa, with a population of 55 thousand, gets the entire 684 area code, and no matter how many open spaces there are, that area code won’t be assigned to United States customers.

All that said, if we were to somehow run out of numbers before the concept of a phone number becomes obsolete, we could simply add a digit to the exchange or area code, as was done in the UK when they ran out.

Sally says:
in the UK all ‘area codes’ for land lines are 5 digits so a typical landline # is 0xxxx-xxxxxx all mobile devices are in the format 07xxx xxxxxx so would seem the easiest option is to prefix the numbers – growing up my number was always 61173 then in then it changed to 601173
joe says:
The solution is usually adding a digit to the prefix rather than suffix. Look at other countries that have run out of numbers such as the UK.
AJ says:
Yep, I am believing that the future of voice communications will be slowly transitioned to general server and networking protocols.. Google, skype, and other networking communications is a good example of this taking place.
While wireless has become the dominant com source, you can bet our increasingly fried microwave airspace will adapt to not only an optional form of Communication IDs but an increasing default of future communication among people in the U.S and around the world.
BlankaK says:
The phone number will be obsolete before you Americans will run out of available numbers. I bet my 0-year kid will NEVER dial a phone number in his life, just perhaps in the open air Dutch historic museum at Arnhem or some other museum. Kids will grow up with data-plans without any minutes or text credits, and have a user-name for their VOIP and video-calls.
BlankaK says:
Oops, dubble post.
Alleged Accomplice says:
Some people need their phones taken away, we can then use those numbers
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Archer9234 says:
David M says:
A standard domestic telephone number has 10 decimal places, (012) 345-6789. Ten decimal places works out to 10 billion possible combinations. Not one billion nor 1.3 billion.

Don’t believe me? 2 decimal places goes 00 through 99 which equals 100 possible numbers. Three decimal goes 000 through 999 which equals 1000 possible numbers….and so on.

The solution is to free up more ten digit numbers that would be allowed to become telephone numbers. There is no reason it is not technically possible.

Given this, we do not need to add more decimal places to a telephone number, with ten decimal places we already have ten billion numbers to choose from.

Rich says:
No, we don’t have 10 billion as there are technical reasons why we can’t use the full range of area codes. We can’t have any area code start with a 0 because that would instantly dial the operator and not complete the rest of the number. We can’t have any area codes starting with 1 because 1 is the US country code. This is why our area codes start at 201 (New Jersey). There are also the 800, 866, 877 and 888 blocks which are specifically reserved for business use only.
David M says:
Even if we subtract out what cannot be used, we still have billions of numbers left which is far more than what we are using now by many fold.
Rich says:
Not really. Area codes are regionally bound by state borders. California can’t exactly ring up Maine and say “Hey, give us 8 million numbers starting with 207. We know you’re not using them because you only have 1.3 million people in your whole state and therefore you won’t miss 8 out of 10 million numbers.” Doesn’t work that way.
Jonathanabby says:
Call Phones can be anywhere, & are not tied to a state. Therefore, California CAN use any other location’s numbers,,and do so, now.
Landline numbers can be anywhere , too.Remember,”Portability” of your phone # ? That means you can keep your old number, when you change carriers, and also locations!
Rich says:
You’re referring to the transfer of an existing number registered to you and not the establishment of a new one. On the establishment of new service, the number you’re given is based on where it is physically, as in the state you’re in. If for example you’re physically in CA and request a brand new ME 207, you will be told no. It’s not supposed to be like that, but if you attempt to establish new service through a local Telco or local wireless carrier that has an area code outside of your registered physical location, you’ll have a very difficult time getting one. Your least-worst solution is to register the number through a VoIP carrier first (like Vonage), then transfer it to your wireless/cellular/Telco provider. It costs extra money, but if you want a specific area code badly enough, that’s the way to go about it.