How long before a phone number is reassigned?

In the US, a phone company has to hold a disconnected personal number for at least 45 days, and no more than 90, before it can give that number to a new customer. A business number can be held for up to 365 days. Those are federal rules, written into 47 CFR 52.15, and the clock starts when the number is disconnected, not when you stop using the phone. A prepaid line you simply stop paying for can take months to reach disconnection, and the waiting period only starts after that. Once the number is reissued, the new owner receives every text message code and reset link still pointed at it.

The rules and the carriers side by side

The table puts the federal rule next to what carriers say on their own support pages. Read the second column first: most of the confusion comes from counting from the wrong day.

The "minimum" and "maximum" are both real. The 45 days is a floor: a carrier cannot hand the number on sooner. The 90 days is a ceiling on how long a carrier can sit on a personal number before it has to go back into stock. Somewhere in that window your old number becomes something a stranger can pick from a list of available numbers.

Why you hear "a few days" and also "years"

Two answers circulate. The "it gets reused almost straight away" story comes from people who changed their number and then heard that someone else was getting their texts within weeks. The "numbers sit unused for a year or more" story comes from people who stopped topping up an old prepaid phone and found the number still worked when they came back.

The rule explains both. The 45 to 90 day window runs from disconnection. If you change your number or cancel a contract, disconnection is immediate, so a stranger can have your old number about six weeks later. If you just stop paying a prepaid line, the account first sits suspended. T-Mobile says a prepaid account left in Not Paid status for more than 120 days may be cancelled and the number lost. Only then does the 45 day minimum start, which puts the earliest reissue at around 165 days after the money ran out. Neither story is wrong; they count from different days.

What the new owner actually gets

A phone number is not retired when you leave it. It goes back into a pool, and the pool is large. Researchers Kevin Lee and Arvind Narayanan at Princeton estimated the stock of available recycled numbers at one carrier at about one million, with a largely fresh set becoming available every month.

Their 2021 study looked at 259 numbers that T-Mobile and Verizon were offering to new subscribers through their websites. They found 215 were recycled and vulnerable to at least one attack, and 171 were tied to existing accounts at popular websites such as Amazon, Facebook, Google, PayPal and Yahoo. A hundred were linked to email addresses that had appeared in data breaches. When they took 200 recycled numbers and simply watched them, 19 were receiving security or privacy sensitive calls and messages meant for previous owners within one week.

That last figure is the practical risk. If an account still uses your old number for the text message code that acts as your second sign-in step, the new owner can receive that code. If a site lets you reset a password by text, the new owner can start that reset.

Verizon's number change page adds a smaller point people miss: anyone calling your old number hears that it is no longer in service, and calls are not forwarded. Texts and voicemails may be lost. A bank still using the old number simply stops reaching you.

What protects you and what does not

There is a federal database built for this problem, but it protects you from the wrong thing. Under 47 CFR 64.1200, carriers report to the Reassigned Numbers Database, on the 15th of every month, the most recent date each number they hold was permanently disconnected. Companies that make calls or send texts can check it before contacting a number, and if they do and the database gets it wrong, they get a legal safe harbor. It exists so that a caller you once gave consent to stops calling or texting a number that now belongs to someone else. Nothing in that rule requires a website to check it before sending you a sign-in code.

Porting is the protection that does work. The same rule says a number that is ported to another provider is not permanently disconnected. Moving your number to a new carrier keeps it yours, with no waiting period and no reissue. Cancelling the old contract first and asking for the number later is the mistake that loses it.

The 2026 disaster waiver shows how fixed the floor is. In April 2026 the FCC lifted the 90 day ceiling for residential customers in Guam and the Northern Mariana Islands after Typhoon Sinlaku, for 270 days, ending January 18, 2027, so carriers could hold numbers for displaced people who asked. The order extends the same relief to areas hit later in 2026 by hurricanes, typhoons, tropical storms, tropical cyclones and wildfires that receive a presidential declaration. It states plainly that the 45 day minimum is not waived.

Where these numbers stop applying

The 45 and 90 day figures are US federal rules for numbers in the North American plan. They do not tell you what happens to a number in another country, and carriers outside the US set their own timetables. In the UK, Vodafone says a pay as you go number with no call or text that costs money for 180 days is disconnected permanently, after a reminder text at 90 days. Receiving calls and texts does not count as use, and Vodafone says it cannot reactivate a disconnected pay as you go number. Its page does not say how long it then waits before giving the number to someone else.

The rules also say nothing about when a reissued number is actually picked: it can sit unchosen for a long time or go the first day it appears. Business lines can be held for up to a year, so a number from a company plan may come back later than a personal one, but it still comes back.

These are the rules as the regulations and carrier pages state them in October 2026. It is general information, not advice about a specific contract.

Before you give up a number

1. Find everything that uses it. Go through your email, bank, phone account, shopping and social accounts and look at the phone number on each one. Your main mailbox comes first, because it can reset everything else, as locking down an email account explains.
2. Move sign-in codes off the number. T-Mobile itself tells customers to remove two-factor authentication from apps that verify by mobile number before changing it. Switch each account to an authenticator app with working backups, or to a passkey, which does not depend on a phone number at all.
3. Update recovery details on purpose. A recovery phone that now belongs to a stranger is a back door, the problem covered in setting up account recovery before you need it.
4. Tell your bank directly. Use the app or the number on your card, not a link in a message, and follow the habits in banking online without handing over the keys.
5. Port instead of cancelling, or park the number. If you are switching carriers, port. If you no longer need the number but cannot be sure every account has moved, the Princeton researchers' main recommendation was to park it on an inexpensive secondary line rather than let it go.
6. Keep the clock in mind for old email too. An old address can be deleted for inactivity just as a number can be reissued, and the deadlines at the big email providers work the same way: let it lapse only after nothing depends on it.

If you are on the other side and your new number keeps receiving codes and messages for someone else, do not use them. Ignore them, and treat any caller who claims a code was sent to you by mistake with the suspicion described in how phone scams and spoofed numbers work.