The fastest way to block a number depends on your phone type

On most phones, you can block a number directly from your call log or contacts app in under a minute. If you have an iPhone, open the Phone app, find the number in your recent calls, tap the information icon next to it, scroll down, and tap "Block this Caller". On Android, open the Phone app, long-press the number in your call history, and select "Block number" from the menu that appears. Some Android phones phrase this as "Add to reject list" instead.

If the number is already saved in your contacts, you can block it from there too. Open the contact, tap the menu icon (three dots on Android, or the information icon on iPhone), and look for a block option. The exact wording and location shift between phone models, but the option is always in the contact details somewhere.

Blocked numbers can still leave voicemails on most phones, though you won't be notified. If you want to prevent voicemails entirely, you'll need to use your carrier's tools instead of your phone's built-in blocker — see the section below on carrier-level blocking.

Key Takeaways

  • Your phone's built-in blocker stops calls and texts from reaching you, but blocked callers can still leave voicemails unless you use your carrier's tools.
  • On iPhone, block a number through the Phone app by tapping the information icon next to a recent call and selecting "Block this Caller".
  • On Android, long-press a number in your call history and select "Block number" from the menu.
  • Your carrier (Verizon, AT&T, T-Mobile, etc.) offers its own blocking service that can prevent voicemails and may catch spam before it reaches your phone.
  • You can unblock a number at any time by finding it in your blocked list and selecting the unblock option.

Blocking a number through your carrier instead of your phone

Your phone company offers blocking tools that work differently from your phone's built-in blocker. Carrier-level blocking stops calls before they reach your phone at all, and it can prevent voicemails from being left. Verizon calls this "Call Filter", AT&T calls it "Call Protect", and T-Mobile calls it "Scam Shield". Each carrier's tool works slightly differently, but all of them let you block numbers through an app or your online account.

To use your carrier's blocker, log into your account on your carrier's website or open their official app. Look for a section labeled "Call Management", "Call Filter", "Call Protect", or "Scam Shield" depending on which carrier you use. From there, you can add numbers to a block list. Some carriers charge a small monthly fee for the full version of their tool, though basic blocking is usually free.

Carrier blocking is worth using if you get repeated calls from the same number and want to prevent voicemails, or if you want your carrier to filter out known spam numbers automatically. Your phone's built-in blocker is faster for one-off numbers, but the two can work together — you can block the same number in both places if you want extra certainty it won't reach you.

What happens when you block a number

When you block a number on your phone, calls from that number go straight to voicemail without your phone ringing. Text messages from blocked numbers are usually hidden in a separate folder or deleted entirely, depending on your phone model. You won't see notifications for either calls or texts from that number.

The person calling you won't hear a message saying they've been blocked. On iPhone, a blocked caller hears a normal ring tone and then gets sent to voicemail, so they may not realize they're blocked. On Android, the behavior varies by carrier — some let the call ring normally before sending it to voicemail, while others may give a busy signal or say the number is unavailable.

Blocked numbers can still see that you've read their text messages if you use iMessage on iPhone, and they can still reach you through other apps like Facebook Messenger or WhatsApp. Blocking only affects calls and texts through your phone's native apps, not third-party messaging services.

Unblocking a number if you change your mind

You can unblock a number at any time. On iPhone, open Settings, go to Phone, scroll down to "Blocked Contacts", and swipe left on the number you want to unblock. On Android, open the Phone app, tap the menu icon, go to "Settings" or "Call settings", find "Blocked numbers" or "Reject list", and select the number to unblock it.

If you blocked the number through your carrier instead, you'll need to unblock it through your carrier's app or website. Log into your account, find the call management section, and remove the number from your blocked list there.

Once you unblock a number, calls and texts from that person will come through normally again. You won't receive any notification that you've unblocked them, and they won't be told that you've done so.

Blocking unknown or private numbers

If you want to block calls from numbers that don't show up on your caller ID — often labeled "Unknown", "Private", or "Restricted" — your phone's built-in blocker won't help, because there's no specific number to block. Instead, you'll need to use your carrier's tools or a third-party app.

Verizon Call Filter, AT&T Call Protect, and T-Mobile Scam Shield all have options to block calls from unknown numbers. You can usually turn this on in the app settings. Be aware that some legitimate callers (like your doctor's office or your bank) may call from private numbers, so blocking all unknown calls might cause you to miss important calls.

If you want more control, consider using a third-party call-blocking app like RoboKiller, Nomorobo, or Truecaller. These apps let you set rules for unknown numbers — for example, you could allow calls from your contacts and block everything else. Most of these apps are free with optional paid versions that add extra features.

Blocking spam and robocalls

Spam and robocalls are harder to block one at a time because the number often changes with each call. Your best defense is to let your carrier's spam filter do the work. Verizon Call Filter, AT&T Call Protect, and T-Mobile Scam Shield all identify and block known spam numbers automatically if you turn on their spam-filtering feature.

If you do get a spam call from a number you can block, go ahead and block it — it won't stop all spam, but it will stop that particular number from calling you again. You can also report the number to your carrier's spam database through their app, which helps them identify patterns and block similar numbers for other customers.

If spam calls are overwhelming, consider using a dedicated spam-blocking app. Apps like RoboKiller use artificial intelligence to identify spam patterns and block calls before they reach you. These apps often cost money, but they're more aggressive about filtering than your carrier's free tools.

Blocking contacts on specific messaging apps

If someone is contacting you through WhatsApp, Facebook Messenger, Instagram, or another app instead of through calls and texts, you'll need to block them within that app, not through your phone's call blocker. Open the conversation with that person, tap their name or profile, and look for a "Block" option. The exact steps vary by app, but the option is always in the contact details or conversation menu.

Blocking someone in an app prevents them from seeing your status updates, sending you messages, or calling you through that app. They won't be notified that you've blocked them, but they may figure it out if their messages stop going through. You can unblock them the same way you blocked them if you change your mind.

If someone is harassing you through multiple apps and you want to stop all contact, blocking them in each app individually is the most thorough approach. You can also report them to the app for harassment, which may result in their account being suspended or removed.

Frequently Asked Questions

Can someone tell if I've blocked their number?

Not directly. On iPhone, a blocked caller hears a normal ring tone before being sent to voicemail, so they may not realize they're blocked. On Android, the experience varies by carrier. Someone might suspect they're blocked if their calls consistently go to voicemail and you never call them back, but they can't know for certain from the phone's behavior alone.

Will blocking a number stop them from texting me?

Yes. Text messages from blocked numbers are usually hidden or deleted depending on your phone model. You won't see notifications for them. The person texting you won't know their messages are blocked — they'll just see that you're not responding.

What's the difference between blocking and muting a contact?

Muting silences notifications from a contact but still lets their calls and texts through to your phone. You can see them if you look, but you won't be alerted. Blocking prevents calls and texts from reaching you at all. Use muting for people you want to hear from but not be interrupted by, and blocking for people you don't want to contact you.

If I block someone, can they still reach me through FaceTime or iMessage?

No. On iPhone, blocking someone prevents them from reaching you through calls, texts, FaceTime, and iMessage. They can still contact you through other apps like WhatsApp or Facebook Messenger, which are separate services.

Can I block a number that's already in my contacts?

Yes. Open the contact, tap the information icon or menu, and select the block option. The contact stays in your phone, but calls and texts from that number will be blocked. You can unblock them at any time without losing the contact information.