Consumer Information Energy Telecommunications
Elizabeth S. Jacobs
Nick Wagner
Board Member
Sheila K. Tipton
Board Member

Area Code Relief Frequently Asked Questions

1. Who is in charge of area codes?

Federal and state regulators share this responsibility. The North American Numbering Plan Administrator (NANPA) is responsible for day-to-day administration, assignment, and management of area codes in the United States.

Congress gave the Federal Communications Commission (FCC) jurisdiction over telephone number administration as a part of the Federal Telecommunications Act of 1996. The FCC delegated to the states the authority to decide when, and in what form, to introduce new area codes. The most common ways of adding new area codes are either by a geographic split or by an overlay. (See question #12.)

The regulators receive advice on number administration issues from the North American Numbering Council (NANC), an advisory body made up of industry participants, consumer advocates, and state regulators.

2. Why do we need new area codes?

The demand for telephone numbers has increased dramatically with the growth of wireless telephone, fax and pager use, and the use of additional lines for Internet access. But this is not the main reason for new area codes.

The 1996 Federal Act marked the beginning of competition for local telephone service. Competing local telephone companies, wireless telephone companies, and paging companies all need inventories of numbers before they offer services to customers. Because the numbering system set up by the telecommunications industry was done in a monopoly environment, telephone numbers are currently given out in blocks of 10,000.

Today there are 792 blocks of 10,000 numbers in each area code (792 x 10,000 = 7,920,000 numbers).

Regulators and others have concluded that numbers are not currently used in an efficient way. Even if a small percentage of the available telephone numbers in an area code is in use, an area code can run out of numbers if all 792 number blocks have been spoken for or allocated. The FCC and state regulatory bodies are investigating the most cost-effective way to increase the efficiency and reduce the need for additional area codes.

3. What will happen if we run out of area codes?

If all of the available area codes are used, our dialing pattern might be expanded by one or more digits to an 11 or 12 digit dialing pattern. Because changing the dialing pattern in this way would require significant time for transition and would involve substantial expense, the FCC and state regulatory bodies have proposed a number of ways to preserve the life of our current ten-digit dialing pattern for as long as possible.

4. Is anyone doing anything to slow down the pace of adding new area codes?

Area code changes are inconvenient for both residential and business customers, so it is important to make the numbers in each area code last as long as possible. The FCC and state regulatory bodies are examining several ideas for improving number utilization.

These ideas include improving the information we have about how telephone numbers are being used and requiring telephone companies to prove that they need new numbers, as well as other, more technical solutions, such as giving telephone numbers to companies in smaller blocks.

5. Why do customers in some states have to dial the area code for local phone calls?

Area code overlays can result in two different end-users in the same geographic area with the same seven-digit local number, but with two different area codes. Existing numbers would use the existing area code but new numbers may be assigned with the new area code. To route local calls to the right destinations, customers must dial ten digits for local calls. In addition, using the area code as a part of local telephone number dialing permits a more complete use of all of the numbers within an area code, extending the life of the area code.

The FCC has required the use of area code numbers when dialing local calls in an area code overlay plan in order to level the playing field, so that new telephone companies can offer their services without a perceived competitive disadvantage.

Without ten-digit dialing, established telephone companies may have a perceived advantage over new telephone companies. Customers could find it less attractive to choose a new telephone company if doing so would mean always dialing ten digits, but choosing an established telephone company would allow them to dial only seven digits.

6. Do other states currently have to dial the area code to make local calls?

More than a dozen states including one as close as Illinois currently use the area code when dialing local calls in some parts of the state.

7. If you dial the area code for every local call, how do you know which calls are toll calls and which are local?

In Iowa toll calls are placed by dialing "1" plus the area code and local calling number. Local calls do not use the "1" prefix.

8. How many numbers are available in each area code?

Theoretically, each area code could include 10 million seven-digit phone numbers. But some numbers are not available – such as seven-digit numbers starting with 0, or 1, or 911. Therefore, each area code has somewhat fewer than 8 million usable numbers (7,920,000).

9. How many area codes are available? How many are used?

There are a total of 680 usable area codes available for assignment. Of that number, 215 are currently in service in the United States (as of June 1, 1999). More than 70 of these may need new area codes within a year or two. By comparison, there were only 119 area codes in service in the United States at the end of 1991.

In addition, over 40 area codes are in service in the other countries that participate in the North American Numbering Plan, including Canada and parts of a number of Caribbean nations.

10. How are numbers allocated to telephone companies?

AT&T designed the area code system in the 1940s to make it possible to route long distance calls automatically.

A telephone number consists of ten digits. The first three digits are the area code, the second three digits are the central office or exchange, and the last four digits are the individual telephone line numbers. There are 10,000 possible combinations of these digits within each exchange.

When a consumer makes a telephone call, the network uses the area code and exchange to determine where to send the call. The area code tells the network the geographic area in which the called party lives, and the exchange indicates the particular switch within that area code to which the call should be routed. This system for routing calls requires numbers to be given out in blocks of 10,000, because each exchange contains 10,000 telephone numbers.

11. Can’t we use smaller telephone number blocks, like blocks of 1,000?

The network routing system currently relies on allocation of numbers in blocks of 10,000. In recent months, telephone number portability has been introduced in many cities throughout the country. Telephone number portability enables consumers to change local telephone companies without having to change their telephone numbers.

The FCC is currently seeking public input on whether to use "number pooling" to alleviate the area code problems. It is possible to use the same databases that make number portability possible to apportion telephone numbers to local telephone companies in smaller blocks, such as blocks of 1,000. It isn't likely the FCC will make any changes in time to affect pending area code change recommendations in Iowa.

12. What is the difference between the "overlay" and a "geographic split" method of adding a new area code?

Geographic split: The geographic area covered by an existing area code is split in two. One section retains the existing area code, while the other receives a new area code.  The benefit of a geographic split is that an area code remains defined as a geographic area – customers know something about the location of the people they are calling. Within each area local dialing remains the same as it is now.  The down-side of a geographic split is that many customers must cope with the inconvenience of changing their area code and some customers along the area code boundary may have to dial the area code to place local calls.

Overlay: As the name suggests, the new area code "overlays" the pre-existing area code, most often serving the identical geographic area. The benefit of an overlay is that customers retain their existing area codes. Only new lines get the new area code. An overlay requires all customers, including those with telephone numbers in the pre-existing area code, to dial area codes for local calls.

13. Why do we have to have extra numbers?

The switches used by telephone companies to route calls are designed to handle seven-digit phone numbers and three-digit area codes. Altering this design would be very expensive and would significantly increase the cost of telephone service. A less costly method is described below.

For technical reasons, numbers are currently assigned in blocks of 10,000. The FCC is currently evaluating a method to cut those blocks down to 1,000. This would help better use numbers. Telephone companies needing small quantities of numbers will be allocated 1,000 numbers, not 10,000. This would significantly reduce the amount of unused numbers. However, cutting blocks of numbers down to 1,000 is much more difficult than it sounds due to the way our telephone network is designed.

14. When will the change take place in Iowa?

The IUB has approved a "split" in the 515 area code. The new 641 area code began being used July 9, 2000 for permissive dialing and became mandatory on December 3, 2000.

The IUB has approved a "split" in the 319 area code. The new 563 area code went into effect on March 25, 2001 with permissive dialing allowed through December 1, 2001.  Mandatory dialing of the new area code began on December 2, 2001.

According to latest projections, the 712 area code will not need a relief plan before 2011.