Why does Google ask for your phone number? Its 4 uses

Google asks for your phone number mainly to block spam sign-ups and to give you a way back into your account. Its own pages list two more uses: helping people find you, and making the ads you see "more relevant." Only the first two need the number. You can turn the others off, or never add a number at all.

That is the short version. The longer one matters because Google's settings for each use sit in different places, and one of them keeps working after you think you have switched it off. Everything below is from Google's own pages as checked on October 20, 2026.

Why does Google ask for a phone number when you create an account?

To make spam accounts expensive. Google's Verify your account page says: "To help protect you and stop spammers, before you create an account or sign in, sometimes phone verification is required to confirm you're a real person."

The phone check works because phone numbers are scarce in a way email addresses are not. Google adds two limits on top: "we limit the number of accounts each phone number can create," and "we limit the number of times a phone number can be used for verification." Someone making thousands of accounts would need thousands of numbers.

That is why the request is "sometimes." Google does not ask everyone, and it does not publish what triggers the check. If it does ask you, a landline call, a trusted person's number or a Google Account on an address you already have can all get you past it.

What Google uses your phone number for

Once a number is on your account, it can do more than the spam check. Google's privacy policy, effective October 16, 2026, puts it plainly: "your phone number can be used to help you access your account if you forget your password, help people find and connect with you, and make the ads you see more relevant to you."

Google's phone number help page breaks this into separate uses. Here they are with the setting that controls each.

(The odd grammar in the last row is Google's.)

To see whether your number is in the last group, open your Google Account, go to Personal info, then Phone. If "Across Google" shows under Usage, the number is used across Google services, ads included.

Can advertisers reach you through your phone number?

Yes, without ever buying it. Google Ads has a feature called Customer Match. An advertiser uploads a list of its customers' emails and phone numbers, scrambled into hashed strings, and Google compares them with its own accounts. In Google's own words: "Google keeps track of the email addresses and phone numbers for Google accounts and the corresponding hashed strings for those email addresses or phone numbers." If there is a match, Google adds that account to the advertiser's audience.

So a shop that already has your number can use it to find your Google account and show you its ads on Search, YouTube and Gmail. Google's page does not say whether the "Better ads" switch affects this matching, so we won't guess either way. For the rest of the ad settings on your account, see our guide on how to stop Google tracking you.

The recovery number trap

Many people delete their phone number to stop the ad use, then add it back as a recovery phone and assume it is now locked to recovery. Google's recovery options page has two warnings about that:

• "If you delete your recovery phone number, it may still be used for other Google services."
• "If your recovery phone number is the same as another phone number you've added to your account, it might be used for other purposes."

Google's own steps for stopping a number being used across Google are: go to the Phone section, select Delete, then Remove number, then "Go to the Recovery phone section of your Google Account and re-add your number." Then check Personal info, Phone again. If "Across Google" is back, the number is still in more than one place. Phones also add numbers on their own: Android verifies the device's number and adds it to every Google Account signed in on it, unless you turn off Phone number verification in the Settings app under Google, All services.

Has a security phone number ever been used for ads?

Yes, though not by Google, as far as any public record shows. Two US cases set the precedent.

• Twitter, 2022. The FTC said "Twitter asked users to give their phone numbers and email addresses to protect their accounts," then let advertisers use that data to target them. More than 140 million users gave their numbers or emails between 2014 and 2019. Twitter agreed to a $150 million penalty (FTC, May 25, 2022).
• Facebook, 2019. The FTC's $5 billion order said Facebook told users it would collect phone numbers for a security feature "but did not disclose that it also used those numbers for advertising purposes," and banned the practice (FTC, July 24, 2019).

A peer-reviewed study published in 2019 had already shown it: phone numbers "provided for security purposes such as two-factor authentication" were used to let advertisers target users, even with all the relevant privacy controls on the researchers' test accounts set to the most private option (Venkatadri et al., PoPETs 2019).

The lesson is not that Google does this. It is that "we need it for security" and "we use it for ads" can live in the same database, and the only thing between them is a setting or a promise.

Is it safe to give Google your phone number?

It depends on what the number does on your account. Three risks are worth weighing.

SIM swapping. If your number is how you sign in or recover your account, whoever controls the number controls a way in. In a SIM swap, a criminal talks your carrier into moving your number to their SIM. The FBI's Internet Crime Complaint Center received 1,611 SIM swapping complaints in 2021, with losses of more than $68 million, up from 320 complaints across 2018 to 2020. The FCC adopted rules in November 2023 requiring carriers to verify customers before moving a number and to notify them of SIM changes. Microsoft now tells its users that "SMS-based authentication is now a leading source of fraud" and that SMS "is vulnerable to phishing and SIM-swap attacks" (Microsoft support).

Linking. Your email address can be changed in a minute. Your phone number usually stays with you for years, across your bank, your doctor, your shops and your messaging apps. Every account that holds it is one more place that can be matched to the others.

Number reuse. Carriers recycle numbers. Microsoft warns that "mobile carriers can reuse phone numbers after 30-days." A number you gave up years ago may now belong to a stranger who can receive your codes.

A reasonable middle path: if you do give Google a number, use it for recovery only, turn off "Better ads and Google services," and switch sign-in to something that does not depend on texts. Our guide on whether two-factor authentication is safe ranks the options.

Why do other email providers ask for your phone number?

Mostly for the same two reasons: spam checks and recovery.

None of this is a law of nature. A provider can fight spam with other checks and handle recovery with something you keep yourself. When we built Secria, we left the phone number out of sign-up entirely: you give a name, the address you want and a password, and recovery runs on a 12-word recovery phrase. More on that, and on which providers ask, on our page about email without a phone number.

Frequently asked questions

Why does Google keep asking for my phone number?

Google's verify page says phone verification is sometimes required "before you create an account or sign in," so the request can come back at sign-in, not only at sign-up. If a number is already on your account, Google says it will "try to re-verify it from time to time to make sure that it's still yours." On Android, the phone can also verify your number automatically.

What happens if I don't give Google my phone number?

For most accounts, nothing breaks. You can still use Gmail and other Google services. The trade-off is recovery: without a phone, you rely on a recovery email, backup codes or a recovery contact, so set those up before you need them.

Can Google see my phone number if I sign in on my phone?

On Android, yes, by default. Google's Android help says phone number verification is on by default and adds the device's verified numbers to all Google Accounts signed in on it. You can turn it off under Settings, Google, All services, Privacy and security.

Does removing my phone number from Google delete it everywhere?

Not always. Google warns that a deleted recovery number "may still be used for other Google services." Check the Phone section of your account afterward, and remove the number from individual services such as Google Pay or Calendar if it shows up there.

A phone number is one of the most permanent things you can give a company. If you would rather your email provider never had it, a free Secria mailbox takes a name, an address and a password, and no phone number.