The fastest way depends on your phone type and what you're blocking

Most phones let you block calls directly in the Phone app without installing anything extra. On iPhone, open the recent call from the number you want to block, tap the info icon, and select "Block this Caller." On Android, open the Phone app, find the number in your call history, press and hold it, then tap "Block number." Both methods stop that specific number from reaching you — calls go straight to voicemail and you won't see a notification.

If you're getting calls from many different numbers or from numbers that keep changing, blocking one at a time won't help. That's when you need a different approach: filtering at the carrier level, using a third-party app, or adjusting your phone's built-in filters. The method you choose depends on whether you want to block specific people, stop robocalls and spam, or silence all unknown numbers.

Key Takeaways

  • iPhone and Android both let you block individual numbers directly in the Phone app without any setup — the call goes to voicemail and you get no notification.
  • Your phone carrier (Verizon, AT&T, T-Mobile, etc.) offers spam filtering at no extra cost, and turning it on catches many robocalls before they reach you.
  • Third-party apps like Nomorobo, RoboKiller, and Truecaller can block calls based on patterns and known spam lists, but require you to grant permission to screen all incoming calls.
  • Blocking "Unknown" or "No Caller ID" numbers stops calls from people hiding their number, but you may miss legitimate calls from doctors, banks, or businesses that use private lines.
  • Do not disturb modes let you silence calls from everyone except your contacts, which works well if you only want to hear from people you know.

Blocking one number on iPhone or Android

On iPhone: Open the Phone app and go to Recents. Find the number you want to block, tap the blue info circle next to it, scroll down, and tap "Block this Caller." You can also block someone from a text message by opening Messages, swiping left on the conversation, tapping the three dots, and selecting "Block this Caller." Once blocked, that number's calls go to voicemail and you won't see missed call notifications.

On Android: Open the Phone app and tap the three dots in the top right corner. Go to Settings, then Blocked Numbers. Tap the plus sign and enter the number you want to block, or find it in your call history, press and hold it, and tap "Block number." The blocked caller will hear a message saying the number is not available, and you won't get a notification that they tried.

To see your blocked list on either phone, go back to the same menu and look for "Blocked" or "Blocked Numbers." You can unblock anyone at any time by finding them in the list and selecting "Unblock."

Using your carrier's spam filter

Verizon, AT&T, T-Mobile, and most other carriers offer spam filtering built into your account at no extra charge. These filters catch many robocalls and spam calls before they reach your phone. The setup is different for each carrier, but you can usually turn it on through your carrier's website, their mobile app, or by calling customer service.

Verizon: read the Verizon Call Filter app or turn on filtering in My Verizon Online under Account Settings. AT&T: Use the AT&T Call Protect app or enable it in your AT&T account online. T-Mobile: Scam Shield is built in — go to your T-Mobile account online and turn on "Scam Block" under Call Protection. Other carriers: Check your carrier's website or call their customer service line to ask about spam filtering options.

Carrier filters work in the background and don't require you to do anything after you turn them on. They block known spam numbers and robocalls based on lists the carrier maintains. Some carriers offer a premium version with more aggressive filtering, but the free version catches most common spam.

Using third-party call-blocking apps

Apps like Nomorobo, RoboKiller, Truecaller, and Whoscall use larger databases of known spam and robocall numbers. They can be more aggressive than your carrier's filter, but they require you to give them permission to screen every call that comes in. This means the app sees the caller's number before your phone does.

Most of these apps are free but show ads or offer a paid version without ads. Some have additional features like call recording or reverse phone lookup. read the app from your phone's app store, open it, and follow the prompts to grant permission to manage calls. Once active, the app will automatically block calls from numbers on its spam list and let you know which calls were blocked.

The trade-off is that these apps have access to your call data. Read the app's privacy policy to understand what information they collect. If you're uncomfortable with that, stick with your carrier's filter or blocking individual numbers manually.

Blocking calls from unknown or private numbers

On iPhone: Go to Settings, then Phone, then Silence Unknown Callers. Turn this on and calls from numbers not in your contacts will be silenced — they'll go straight to voicemail and won't ring or show a notification. You can still see them in your voicemail list later.

On Android: Open the Phone app, tap the three dots, go to Settings, then Blocked Numbers, then turn on "Block Unknown." Unknown calls will be declined automatically.

This method is useful if you only want to hear from people in your contacts, but be aware that some legitimate calls come from private or unknown numbers — doctor's offices, banks, government agencies, and businesses often use switchboard numbers that don't show their real caller ID. If you turn this on, check your voicemail regularly so you don't miss important calls.

Using Do Not Disturb to silence calls

On iPhone: Go to Settings, then Focus, then Do Not Disturb. Turn it on and set it to allow calls only from your Favorites or Contacts. You can schedule it to turn on automatically at certain times (like bedtime or work hours) or set up it manually when you need quiet.

On Android: Go to Settings, then Notifications, then Do Not Disturb. Turn it on and choose which contacts are allowed to reach you. You can also set a schedule so it turns on and off automatically.

Do Not Disturb is different from blocking — the calls still come in, but your phone doesn't ring or notify you. The caller doesn't know they've been silenced. This works well if you want to avoid calls during certain times but don't want to permanently block anyone.

What to do if blocking isn't stopping the calls

If you're still getting calls after blocking individual numbers, the caller is likely using a different number each time. This is common with robocalls and spam operations. In this case, blocking one number won't help — you need to use your carrier's spam filter, a third-party app, or the "block unknown callers" feature instead.

If the calls are harassing or threatening, document them by saving voicemails and noting the dates and times. Report them to your carrier's abuse team and to the Federal Trade Commission at reportfraud.ftc.gov. If the calls are from a specific person you know, you may also have legal options — contact your local police non-emergency line or a lawyer for information.

Frequently Asked Questions

Will the person I block know I blocked them?

No. When you block someone, their calls go to voicemail and they won't get a notification that they were blocked. They may suspect it if their calls always go to voicemail, but your phone doesn't tell them.

Can I block calls from a specific area code?

Most phones don't have a built-in way to block entire area codes, but some third-party apps like Nomorobo offer this feature. Your carrier's spam filter may also catch many calls from known spam area codes automatically.

What happens if I block someone and they text me?

Blocking usually applies to both calls and texts. On iPhone, blocked contacts can still reach you through iMessage if you have iMessage turned on — you can turn off iMessage or block them there separately. On Android, blocking typically covers both calls and SMS.

Can I unblock someone after I block them?

Yes. Go back to your blocked list in the Phone app settings and tap "Unblock" next to their name. Once unblocked, they can call and text you normally again.

Why do some calls say "Unknown" or "No Caller ID"?

Some callers use technology to hide their real number, or they're calling from a system that doesn't transmit caller ID information. Doctors' offices, banks, and some businesses do this. If you block all unknown numbers, you may miss these calls — check your voicemail to see if they left a message.