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

On an iPhone, open the Phone app, find the number in your recent calls or messages, tap the info icon (circle with an "i"), 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". Both phones also let you block directly from a text message: swipe left on iPhone or long-press on Android, then choose the block option.

If you don't have the number saved as a contact, you can still block it the same way — the phone doesn't need a name to create a block. Once blocked, calls and texts from that number go straight to voicemail (iPhone) or are silently rejected (Android), and you won't see notifications.

For landlines or older phones without a built-in block feature, your phone company may offer call blocking through their network. Contact your provider directly to ask whether they support blocking at the carrier level — this works even if your phone itself can't block.

Key Takeaways

  • iPhone users can block a number in three taps from the Phone app's recent calls list or from any message thread.
  • Android users long-press a number in the Phone app and select "Block number" from the menu that appears.
  • Blocked calls go to voicemail on iPhone and are silently rejected on Android, with no notification to you.
  • If your phone doesn't have a built-in block feature, ask your phone company whether they offer network-level call blocking.
  • You can unblock a number at any time by going back to the same menu and selecting "Unblock".

What happens when you block a number

The blocked caller will not hear a message saying they've been blocked. Instead, on most carriers, their call rings once or twice and then goes to your voicemail as if your phone is off or you're not answering. They may not realize they're blocked — they might think you're just not picking up.

Text messages from a blocked number are also silently rejected. The sender won't receive a delivery confirmation or a bounce-back message. On your end, you won't see any record of their calls or texts unless you go into your phone's settings and look at the block list itself.

If the same person calls from a different number, that new number is not automatically blocked. Each number must be blocked separately. This is why people who are determined to reach you might try calling from a different phone.

Blocking unknown or private numbers

If you're getting calls from numbers that show as "Unknown" or "Private", blocking works differently because there's no specific number to block. Instead, you can use your phone's Do Not Disturb or Focus mode to silence calls from numbers not in your contacts.

On iPhone, go to Settings > Focus > Do Not Disturb, turn it on, and set it to allow calls only from contacts. On Android, go to Settings > Notifications > Do Not Disturb and choose "Calls and messages" or "Calls only", then set it to allow only contacts. This way, unknown callers won't reach you, but people you know will still get through.

Some phone companies also offer a service called Call Filter (T-Mobile and Sprint), Call Protect (AT&T), or Call Guard (Verizon) that automatically screens likely spam calls before they reach you. These services vary by carrier and may cost extra, so check your provider's website to see what's available.

Using third-party call blocking apps

Apps like Nomorobo, RoboKiller, and Truecaller offer more aggressive blocking and can filter calls based on patterns rather than just a single number. These apps maintain databases of known spam and scam numbers and block them automatically, even if you haven't reported them yourself.

The trade-off is that third-party apps need permission to access your call history and contacts, and some collect data about the calls you receive. Read the app's privacy policy before installing it. Free versions usually block calls but show ads; paid versions remove ads and add features like call recording or spam detection.

On iPhone, third-party apps can't block calls the way Android apps can — Apple limits what apps are allowed to do with the Phone app. Instead, iPhone apps can only filter calls in the Phone app's interface, so you still see them listed but marked as filtered. On Android, apps have more control and can block calls before they reach you at all.

Blocking calls from specific types of numbers

If you're getting calls from businesses, charities, or survey companies, you can block them one at a time, but a faster approach is to register with the National Do Not Call Registry. This tells telemarketers and nonprofits that you don't want to receive calls. You can register online at donotcall.gov or by calling 1-888-382-1222 from the phone you want to register.

Registration is free and permanent — it doesn't expire. However, it doesn't stop calls from political organizations, charities, or companies you've done business with in the past 18 months. It also doesn't stop scammers, who ignore the registry entirely. For those, blocking individual numbers or using a call filter app is more effective.

If you're getting calls from debt collectors, credit card companies, or other creditors, you can send them a written request to stop calling. Under the Fair Debt Collection Practices Act, they must honor a written cease-and-desist letter. Send it certified mail to the address on your bill or statement. After that, they can only call to confirm receipt of the letter or to tell you they're taking legal action.

Unblocking a number if you change your mind

On iPhone, go to Settings > Phone > Blocked Contacts, find the number, swipe left, and tap "Unblock". On Android, open the Phone app, go to Settings > Blocked numbers, find the number, and tap the minus sign or "Unblock".

Once unblocked, that person can call and text you normally again, and you'll receive notifications as usual. You can block and unblock the same number as many times as you need to.

When blocking doesn't work

If you block a number but keep getting calls from it, the caller may be spoofing their number — using technology to make their call appear to come from a different number each time. Spoofing is common with scam calls. In this case, blocking individual numbers won't solve the problem because each call looks like it's coming from a new number.

If this is happening, use your phone's Do Not Disturb mode to allow only contacts through, or install a call filter app that can detect patterns in spam calls rather than relying on individual numbers. You can also report the calls to the Federal Trade Commission at reportfraud.ftc.gov, which helps law enforcement track down scammers.

If someone is harassing you repeatedly despite blocking, or if the calls are threatening, contact your local police department and ask about filing a report for harassment or stalking. Your phone company may also be able to help — some carriers offer additional tools or can escalate cases to law enforcement.

Frequently Asked Questions

Can someone tell if I've blocked them?

No. When you block a number, the caller hears a ring or two and then your voicemail, just like when you're unavailable. They won't receive a message saying they've been blocked. They might suspect it if you never respond to calls or texts, but they can't know for certain.

Will blocking a number stop them from texting me?

Yes. Text messages from a blocked number are silently rejected on both iPhone and Android. The sender won't know the message didn't go through — they won't receive a delivery failure notice.

What's the difference between blocking and Do Not Disturb?

Blocking stops a specific number from reaching you at all. Do Not Disturb silences all calls and texts except from people in your contacts. Use blocking for one person you want to avoid; use Do Not Disturb when you want quiet time but still want close contacts to reach you.

If I block someone, can they leave me a voicemail?

On iPhone, blocked callers can leave a voicemail, but you won't be notified and it won't appear in your main voicemail inbox — it goes to a separate "Blocked Messages" folder. On Android, blocked callers typically can't leave a voicemail at all.

Do I need to pay for call blocking?

No. Your phone's built-in block feature is free. The National Do Not Call Registry is free. Your phone company's basic call filter may be free or cost a few dollars per month. Third-party apps are usually free with ads, or a few dollars per month for ad-free versions.