# How many usable phone numbers in an area code? **URL:** \ **Category:** Factual Questions\ **Created:** [June 16, 2004, 8:07pm UTC](https://boards.straightdope.com/t/how-many-usable-phone-numbers-in-an-area-code/250724 "2004-06-16T20:07:26Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![The\_Controvert](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@The\_Controvert](https://boards.straightdope.com/u/The_Controvert)\ **Post date:** [June 16, 2004, 8:07pm UTC](https://boards.straightdope.com/t/how-many-usable-phone-numbers-in-an-area-code/250724/1 "2004-06-16T20:07:26Z")
Ok, 7 digits. Can’t start with 0 or 1. That cuts it to 8 million. Can’t start with 555, 911, 411, etc. Rough guesstimate is that it’s over 7 million. Can we get more precise? ---
**Author:** ![Ms2001](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ms2001/32/18463_2.png) [@Ms2001](https://boards.straightdope.com/u/Ms2001)\ **Post date:** [June 16, 2004, 8:39pm UTC](https://boards.straightdope.com/t/how-many-usable-phone-numbers-in-an-area-code/250724/2 "2004-06-16T20:39:35Z")
Number of prefixes, 000-999: 1000 Remove 555, 0xx, and 1xx: 799 prefixes left Remove x11: 791 prefixes left At 10,000 numbers per prefix, that would be 7.91 million numbers per area code. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 16, 2004, 11:33pm UTC](https://boards.straightdope.com/t/how-many-usable-phone-numbers-in-an-area-code/250724/3 "2004-06-16T23:33:04Z")
And for the “old-timers” who may recall otherwise from the days of mechanical switching systems - 0 and 1 used to be reserved digits that could not be the middle digit of a prefix. Original usage was area codes had 0 or 1 as the middle digit, but that’s no longer the case as the current computerized switches don’t care. ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [June 17, 2004, 12:10am UTC](https://boards.straightdope.com/t/how-many-usable-phone-numbers-in-an-area-code/250724/4 "2004-06-17T00:10:29Z")
Just because there are 7.91 million phone numbers per area code doesn’t mean that there are 7.91 million numbers per area code. Granted [this story](http://members.cox.net/mathmistakes/phone.htm) is about 5 years old and things may have changed since then, but I don’t think so. FTR, it is [NANPA](http://www.nanpa.com/) that doles out the area codes in North America. Despite the fact that there are still plenty of phone numbers available in most area codes, it looks like the FCC is toying with the idea of adding an additional number to [area codes](http://news.com.com/2100-1033-870832.html) and exchanges based on a recommendation: > [@](#): > > But one industry organization has already drawn up a plan for a 12-digit future. Eight years in the making, a report by the Alliance For Telecommunications Industry Solutions (ATIS) proposes adding an extra number to every new area code and dialing prefix. Instead of a telephone number like 415-555-1212, the number would be 4151-5555-1212. > > Adding the two digits would create a well of 640 billion more telephone numbers. But telephone companies would need at least 10 years of work to make the appropriate changes, according to the report. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [June 17, 2004, 12:49am UTC](https://boards.straightdope.com/t/how-many-usable-phone-numbers-in-an-area-code/250724/5 "2004-06-17T00:49:35Z")
The rate of telephone-number takeup has slowed dramatically in the NANP in the last few years. As methods of assigning telephone numbers become more efficient (you no longer have to give an entire exchange of 10000 numbers to a phone company with only a dozen customers in the area, for instance), many plans to add area codes have been delayed or even cancelled. We won’t be needing twelve-digit numbers anytime with the next couple of decades. Which is good, because it will take that long to revamp the entire phone-switching system to accomodate them. ---
**Author:** ![chaoticbear](https://avatars.discourse-cdn.com/v4/letter/c/f07891/32.png) [@chaoticbear](https://boards.straightdope.com/u/chaoticbear)\ **Post date:** [June 17, 2004, 10:44am UTC](https://boards.straightdope.com/t/how-many-usable-phone-numbers-in-an-area-code/250724/6 "2004-06-17T10:44:58Z")
No, actually, 555- is a valid prefix. Looking through our Fayetteville, Arkansas phone book, (Ok, I’m not actually doing that, I’m in Germany) you can see many 555- numbers.