The fastest way depends on your phone type

On most phones, you can block a number directly from a recent call or text message in under 10 seconds. Open your phone's call log or messages, find the number you want to block, press and hold it, and select "Block" or "Block Number" from the menu that appears. The exact wording and location of this option varies slightly between iPhone and Android, but the principle is the same on both.

If you do not have a recent call or message from the number, you can also block it through your phone's settings. On iPhone, go to Settings > Phone > Blocked Contacts, then tap "Add New" and enter the number. On Android, open the Phone app, tap the three-dot menu, select "Settings" > "Blocked Numbers," and add the number manually.

Some carriers also let you block numbers through their own apps or websites, which can be useful if you want to manage blocks across multiple devices or if your phone's built-in blocking is not working as expected.

Key Takeaways

  • The fastest way to block a number is to find it in your call log or messages, press and hold it, and tap "Block Number."
  • If you do not have a recent call or message from the number, you can add it manually through your phone's Settings app under Blocked Contacts or Blocked Numbers.
  • Blocked callers will hear a message saying the call cannot go through, or their call will go straight to voicemail, depending on your phone and carrier.
  • You can unblock a number at any time by finding it in your blocked list and selecting "Unblock."
  • Your carrier may offer additional blocking tools through their app or website, including options to block entire categories of calls like spam or unknown numbers.

What happens when you block a number

When you block a number on your phone, calls and text messages from that number will no longer reach you. On iPhone, blocked callers typically hear a message saying the call cannot go through. On Android, the behavior depends on your phone model and carrier, but usually the call goes straight to voicemail or the caller hears a busy signal.

The blocked person does not receive a notification that they have been blocked — they simply experience the same outcome every time they try to call or text. Text messages from blocked numbers may still appear in your messages app, but you will not receive a notification when they arrive.

Blocking is not permanent. You can unblock a number at any time by going back to your blocked list and selecting "Unblock" next to the number.

Blocking through your carrier

Your mobile carrier — Verizon, AT&T, T-Mobile, or another provider — may offer its own call-blocking service separate from your phone's built-in tools. These carrier services sometimes cost money (typically $2 to $5 per month) but can block entire categories of calls, such as spam, robocalls, or calls from unknown numbers.

Verizon offers Call Filter, AT&T offers Call Protect, and T-Mobile offers Scam Shield. Each has a free version with basic blocking and a paid version with more features. You can download these apps from your carrier's website or your phone's app store, or manage them through your carrier's online account.

Carrier-level blocking can be more effective than phone-level blocking for spam and robocalls because it stops the call before it reaches your phone. However, for blocking a specific person's number, your phone's built-in blocking is usually sufficient and requires no additional cost.

Blocking on older phones and feature phones

If you use an older phone or a basic feature phone without a touchscreen, the process for blocking a number is similar but the menu options may be labeled differently. Look for "Call Settings," "Security," or "Do Not Disturb" in your phone's main menu, then search for an option like "Block Calls" or "Reject List."

Some older phones require you to enter the number manually into a rejection list rather than selecting it from your call log. Check your phone's user manual or contact your carrier's customer service for the exact steps, as the process varies widely depending on the phone model.

If your phone does not have a built-in blocking feature, your carrier may still be able to block numbers for you. Call your carrier's customer service line and ask them to add the number to a rejection list on their end.

Blocking unknown or private numbers

If you want to block all calls from unknown or private numbers — those that show up as "Unknown," "Private," or "No Caller ID" — you can usually do this through your phone's settings without blocking individual numbers. On iPhone, go to Settings > Phone > Silence Unknown Callers, which sends calls from unknown numbers straight to voicemail. On Android, open the Phone app, tap the three-dot menu, go to Settings > Blocked Numbers, and toggle on "Block Unknown."

Be aware that blocking all unknown numbers means you may miss important calls from doctors' offices, banks, or other organizations that use private numbers. A safer approach is to block only the specific numbers that are bothering you and let unknown calls ring through to voicemail.

What to do if blocking is not working

If you are still receiving calls or texts from a number you blocked, the issue is usually one of three things: the person is calling from a different number each time, your phone's blocking feature did not save properly, or the number is spoofed (meaning the caller is using a fake number).

First, check that the number is actually in your blocked list. Go back to your blocked contacts and confirm the number is there. If it is not, add it again and make sure you tap "Save" or "Confirm" before leaving the screen.

If the number is in your blocked list but you are still receiving calls, the caller may be using a different number each time. In that case, block each new number as it appears. If you are receiving many calls from different numbers that seem related, contact your carrier and ask about their spam-blocking service, which can catch patterns that your phone cannot.

If the calls are coming from a spoofed number — a number that looks like it is from your own area code or a trusted organization — your carrier's spam filter is your best option. Enable Call Filter, Call Protect, or Scam Shield through your carrier, as these services are designed to catch spoofed calls that your phone's blocking cannot stop.

Blocking numbers on messaging apps

If someone is contacting you through a messaging app like WhatsApp, Facebook Messenger, or iMessage rather than through regular text messages, you can block them within that app as well. Open the conversation with the person, press and hold their name or message, and look for a "Block" option.

Blocking someone in a messaging app prevents them from sending you messages, seeing your online status, or viewing your profile picture within that app. However, they can still call you on your regular phone line unless you also block their phone number through your phone's settings.

If you want to block someone completely, block their phone number through your phone's settings and also block them in any messaging apps you use.

Frequently Asked Questions

Can someone tell if I blocked them?

No. The blocked person will not receive a notification that they have been blocked. They will simply experience the same outcome every time they try to call or text — either a message saying the call cannot go through, or the call going to voicemail. They may eventually realize they have been blocked if the pattern continues, but your phone does not tell them directly.

What if I block a number by mistake?

You can unblock a number at any time. On iPhone, go to Settings > Phone > Blocked Contacts, find the number, and swipe left to unblock it. On Android, open the Phone app, tap the three-dot menu, go to Settings > Blocked Numbers, find the number, and tap the minus sign next to it. The person will be able to reach you again immediately after you unblock them.

Does blocking a number also block text messages?

Yes. When you block a number on your phone, both calls and text messages from that number are blocked. On some phones, text messages from blocked numbers may still appear in your messages app, but you will not receive a notification when they arrive.

Can I block a number that is not saved in my contacts?

Yes. You can block any number, whether it is saved in your contacts or not. If you have a recent call or message from the number, the fastest way is to find it in your call log or messages and select "Block." If you do not have a recent call or message, you can add the number manually through your phone's Settings app.

Will blocking a number stop spam calls?

Blocking individual numbers will stop calls from those specific numbers, but if you are receiving spam calls from many different numbers, blocking them one at a time is not practical. Instead, enable your carrier's spam-blocking service like Verizon Call Filter, AT&T Call Protect, or T-Mobile Scam Shield, which can block entire categories of spam and robocalls automatically.