Will the U.S. Ever Run Out of Telephone Numbers? (2024)

By: Kate Morgan|Feb 15, 2023

Will the U.S. Ever Run Out of Telephone Numbers? (1)

Phone numbers, as we know them, may be endangered. While there are billions of potential digit combinations, it's not an infinite number. Eventually, it's very possible we'll have used up every available phone number.

Most people are familiar with the modern 10-digit U.S. phone number with an area code. But that's actually a fairly recent invention.

Contents

  1. The History of Phone Numbers
  2. The Introduction of the Area Code
  3. Are Phone Numbers Recycled?
  4. What Will Happen When the Numbers Run Out?

The History of Phone Numbers

Prior to the 1960s, the telephone system used something called the 2L-5N — or two letters, five numbers — format. The letters would be the first two letters of a word, typically the name of a neighborhood, and the numbers corresponded to the individual you were calling. An oft-cited example is Lucy and Ricky Ricardo's phone on the TV show "I Love Lucy." Their phone number was MU 5-9975, for their Murray Hill neighborhood.

To dial a phone number in those days, you'd pick up the phone and speak to a real human operator, who'd physically plug you into the telephone network you were trying to reach. It was easy enough to do for local calls, but long distance got a bit complicated, and as the phone network grew, it called for a new system. A seven-digit system called "all number calling" ditched the letters. Instead, the first three digits corresponded to a telephone provider, while the last four identified the phone-owner. Soon, even that wasn't enough.

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The Introduction of the Area Code

Enter the area code. In 1951, the North American Numbering Plan Administrator (NANPA) — governors of the U.S. phone number system — added the first three-digit area code, New Jersey's, which was 201. At first, there were 86 area codes. Currently there are 335 total area codes, but the phone numbers associated with them are going fast.

"There are area codes that become exhausted," says Kylie Dick, a sales manager for phone number management company NumberBarn. "There's only a certain number of them within each, and once they're gone, they're gone."

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Are Phone Numbers Recycled?

That's not to say numbers don't sometimes reenter circulation. "We get a lot of customers asking if we have a 'fresh, clean, unused number,'" says Dick. "At this point, most numbers are 'recycled,' so at one point in their history they were probably used by someone and then [the numbers] went back to the carrier."

But when an area code is close to being "exhausted," meaning all its numbers have been assigned, NANPA introduces a new area code for that region. But area codes, too, are finite. There are 800 possible three-digit combinations (using 0 or 1 as the first digit of an area code is invalid), but many are unusable (think 911) or reserved for official use. Ultimately, the math works out to a bit more than 5 billion total available phone numbers. In North America, well over half of those are already assigned.

What Will Happen When the Numbers Run Out?

Some plans have been proposed to add more digits. A report created by the Alliance For Telecommunications Industry Solutions explained that adding one digit to the area code and one to the dialing prefix would create an additional 640 billion possible numbers. But it would be much easier said than done: Everything formatted for a 10-digit number would have to be altered to work with two extra digits.

Others believe that by the time 10-digit numbers near total exhaustion, the world will have transitioned away from telephony and toward internet-based calling. In that future, it's difficult to believe 10-digit numbers would be anything but obsolete. "One way or another, your phone number will eventually become a coding afterthought," wrote Drew Magary for Vice.

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We're certainly not there yet though, says Dick. Phone numbers remain a hot commodity, and the shortage of certain desirable numbers or area codes only serves to increase demand.

"There are certain patterns of numbers that people are trying to purchase," she says. "They're wanting a number that is highly memorable. It just makes for easier marketing."

Now That's Interesting

One of the most famous phone numbers in rock history came from power pop band Tommy Tutone with the 1981 hit "867-5309/Jenny," which hit the No. 1 spot on The Billboard Top Tracks in 1982.

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Will the U.S. Ever Run Out of Telephone Numbers? (2024)

FAQs

Will the U.S. Ever Run Out of Telephone Numbers? ›

While there are billions of potential digit combinations, it's not an infinite number. Eventually, it's very possible we'll have used up every available phone number. Most people are familiar with the modern 10-digit U.S. phone number with an area code. But that's actually a fairly recent invention.

How do we not run out of phone numbers? ›

An organization called the Alliance For Telecommunications suggests adding one digit to the area code and one to the dialing prefix. That would add 640 billion more possible numbers.

How many phone numbers can there be in the US? ›

Well, this could turn out to be a simple permutation problem: you have ten number choices (0-9) for each digit of a phone number and repetitions are allowed. Technically, there could be as many as 10 10 = 10 , 000 , 000 , 000 , or 10 billion possible phone numbers in the U.S.

Will the US run out of area codes? ›

Will the US Run Out of Area Codes? The US is estimated to run out of three-digit area codes in 2049. To solve the issue, phone numbers will have to go from being 10 digits to 12 digits long.

Can phone numbers be discontinued? ›

Generally telecom providers reassign numbers within 90 days from when they had become deactivated but there is no specific time limit. In certain area codes with high demand for recycled numbers, the reassignment will occur much more quickly.

Can the US run out of phone numbers? ›

While there are billions of potential digit combinations, it's not an infinite number. Eventually, it's very possible we'll have used up every available phone number. Most people are familiar with the modern 10-digit U.S. phone number with an area code. But that's actually a fairly recent invention.

What happens if an area code runs out of phone numbers? ›

These numbers represent a specific geographic area in North America. Each area code can support up to 792 combinations of the first three digits of a telephone number (known as an exchange code) and when these combinations are depleted, the area code is said to be exhausted. Once exhausted, a new area code is required.

How long until we run out of area codes? ›

So what's going to happen when we eventually run out of area codes? There are currently a total of 335 area codes, with 18 of them being non-geographic. An analysis of the North American Numbering Plan estimates that the current structure is good until around 2049. After that, some changes are going to be needed.

Will the US run out of zip codes? ›

But even so, there are fewer than 99 ZIPs handled by each Sectional Center Facility, which means that even as the country's population continues to grow, the mail will still be able to ZIP comfortably along.

What is the oldest phone number still in use? ›

The number is now written as 1-212-736-5000. According to the hotel's website, PEnnsylvania 6-5000 is New York's oldest continually assigned telephone number and possibly the oldest continuously-assigned number in the world.

Does your old number get reused? ›

What is phone number recycling? Phone number recycling is the industry term that refers to the event when that deactivated/disconnected number gets reassigned to someone else. Typically, it takes at least 90 days for this reassignment to take place but it can be faster in high-demand area codes (212, 310, etc.).

Can phone numbers expire? ›

Phone numbers can expire due to various reasons, such as inactivity or changes in service providers. Inactivity might result in reassigning numbers to other users, optimizing available resources.

Are all US phone numbers 10 digits? ›

The standard US telephone number is a 10-digit number, such as (555) 555-1234, where the first three digits are the "area code".

How many 10-digit combinations are there? ›

Applying these two facts to our scenario gives the following: When repetition is allowed, the number of possible permutations of 10 digits is 1010, or 10,000,000,000. When repetition is not allowed, the number of possible permutations of 10 digits is 10!, or 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 3,628,800.

Do phone numbers get deactivated? ›

A deactivated phone number is one that a mobile operator has taken out of service for an end user, either because the end user has switched operators or has otherwise closed their account. Eventually, all deactivated numbers are recycled and activated for new subscribers.

How long is a phone number out of circulation? ›

To reduce unwanted and intrusive calls intended for a phone number's previous owner, the Commission now requires service providers to regularly report permanent number disconnections and to wait a minimum of 45 days before reassigning a disconnected number to a new user.

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