The fastest way depends on your phone type and carrier

Most phones let you block a number directly from the phone app or contacts — you find the number, tap a menu, and select block. The exact steps differ between iPhone and Android, and some carriers offer additional blocking through their own apps or online accounts. If you are being harassed repeatedly, your carrier may also have a free service that catches spam before it reaches you.

The method you choose matters because some blocks only silence calls and texts from that number on your device, while others prevent the caller from reaching you at all. Device-level blocking is faster to set up. Carrier-level blocking stops the call before it uses your minutes and works even if someone calls from a different phone.

Key Takeaways

  • On iPhone, open the phone app, find the number, swipe left, and tap Block This Caller; on Android, long-press the number in your call log and select Block.
  • Blocking on your device prevents calls and texts from showing up, but the caller may not know they are blocked and could try other numbers.
  • Most carriers offer free spam-blocking services through their network that stop calls before they reach your phone, separate from device blocking.
  • If someone is harassing you repeatedly, document the calls and contact your carrier's abuse team or local police rather than blocking alone.

Blocking a number on iPhone

Open the Phone app and go to Recents. Find the number you want to block, swipe left on it, and tap the red circle with a line through it. A menu appears — tap Block This Caller. The number is now blocked on your device.

You can also block from Contacts: open Contacts, find the person, tap the info button (the circle with an i), scroll down, and tap Block This Caller. If you want to unblock later, go to Settings, Phone, Blocked Contacts, find the number, and tap Unblock.

Blocked callers will not see a message saying they are blocked — their call will straightforward ring on their end and go to voicemail, or they may get a message that the number is unavailable. They will not know whether you blocked them or your phone is off.

Blocking a number on Android

Open the Phone app and go to your call log (Recents). Long-press the number you want to block until a menu appears. Tap Block or Block Number. The number is now blocked on your device.

You can also block from Contacts: open Contacts, find the person, tap the three dots or menu icon, and select Block Number. If you need to unblock, go to Phone settings, find Call Blocking or Blocked Numbers, locate the number, and tap Unblock.

Like iPhone, blocked callers will not receive a notification that they are blocked. Their call will go to voicemail or fail to connect. The exact behavior depends on your phone model and Android version.

Using your carrier's blocking service

Most carriers offer free spam and harassment blocking that works at the network level, meaning calls are stopped before they reach your phone. These services often catch known spam automatically without you having to do anything.

Verizon offers Call Filter (free version available), AT&T offers Call Protect, and T-Mobile offers Scam Shield. You can turn these on in your carrier's app or online account. Some carriers also let you report a number as spam or harassment, which helps their system block it for other customers.

Carrier-level blocking is stronger than device blocking because it stops the call from using your minutes and works even if the caller tries a different phone number. However, you still need to set it up — it does not happen automatically on all carriers.

What happens when you block someone

When you block a number on your device, calls and text messages from that number no longer appear on your phone. They do not show in your call log, and you will not get a notification. The caller does not receive a message saying they are blocked.

Blocked callers may hear a busy signal, be sent to voicemail, or hear a message that the number is unavailable. The experience varies by carrier and phone type. Some callers may not realize they are blocked and may try again or call from a different number.

If the same person keeps calling from different numbers, blocking individual numbers becomes ineffective. In that case, contact your carrier's abuse team or local police if the calls are threatening or harassing.

Blocking unknown or private numbers

If you want to block all calls from unknown numbers or private callers, you can do this at the device level. On iPhone, go to Settings, Phone, Silence Unknown Callers — this sends calls from numbers not in your contacts to voicemail. On Android, open Phone settings, find Call Blocking, and enable Block Unknown or Block Private Numbers.

Be aware that some legitimate calls come from unknown numbers — doctors' offices, banks, and delivery services sometimes call from numbers that do not show up in your contacts. If you enable this, check your voicemail regularly so you do not miss important calls.

Carrier-level spam filters are often better for this purpose because they can distinguish between legitimate businesses and actual spam, whereas device-level blocking treats all unknown numbers the same way.

When to contact your carrier or police

If someone is calling repeatedly after you have blocked them, calling from multiple numbers, leaving threatening messages, or calling at hours that suggest intent to harass, contact your carrier's abuse team. Most carriers have a phone number or online form for reporting harassment. They can investigate and may be able to block the caller at the network level or take other action.

If the calls are threatening, include threats of violence, or are part of a pattern of stalking or harassment, you can also file a report with local police. Keep records of the dates, times, and content of the calls. Some police departments will not act on a single call, but a pattern of behavior is taken more seriously.

Your carrier may also be able to provide call records to police if you file a report. Do not rely on blocking alone if you feel unsafe — blocking only prevents you from seeing the calls, not from being targeted.

Frequently Asked Questions

Can someone tell if I blocked them?

No direct notification is sent. However, if they call repeatedly and always get voicemail or a busy signal, they may suspect they are blocked. The only way to know for certain would be to call you from a different number and see if that call goes through.

What if I block someone by mistake?

You can unblock them at any time. On iPhone, go to Settings, Phone, Blocked Contacts, find the number, and tap Unblock. On Android, go to Phone settings, find Blocked Numbers, locate the number, and tap Unblock. They will be able to reach you when ready after you unblock.

Does blocking stop text messages too?

Yes. When you block a number on your device, both calls and text messages from that number are blocked. They will not appear in your messages app, and you will not get a notification. The sender will not know their message was blocked.

Will blocking work if someone calls from a different number?

No. Blocking only affects the specific number you blocked. If the same person calls from a different phone, that call will come through. If you are being harassed from multiple numbers, contact your carrier or police rather than blocking each number individually.

Is carrier blocking better than device blocking?

Carrier blocking is stronger because it stops calls at the network level before they reach your phone. Device blocking is faster to set up and works when ready. For spam, use both — enable your carrier's spam filter and block individual numbers on your device if they keep calling.