The fastest way depends on your phone type
Most phones let you block a number directly from the call log or contacts app without installing anything extra. On iPhone, open the Phone app, find the number you want to block, tap the info icon, scroll down, and select "Block this Caller." On Android, open the Phone app, long-press the number in your call history, and tap "Block number" — the exact wording varies by manufacturer, but the option is always in the call log or contacts menu.
If you want to block calls before they reach you, your phone carrier offers this too. Call your provider's customer service line (the number is on your bill) and ask them to activate call blocking on your account. They can usually block a specific number within hours, though some carriers charge a small monthly fee for this service while others include it free.
For spam calls from numbers that change constantly, a third-party app often works better than blocking individual numbers. Popular options include TrueCaller, RoboKiller, and Nomorobo, which use databases of known spam numbers to filter calls before they ring your phone.
Key Takeaways
- You can block a single number directly in your phone's call log or contacts app in under a minute, and the blocked caller will see your phone ring but you will not hear it.
- Your phone carrier can block numbers on your account, which stops the call from reaching your phone at all, though some carriers charge a monthly fee.
- Third-party apps like TrueCaller and RoboKiller use spam databases to block unknown numbers automatically, which works better than manual blocking for robocalls.
- Blocking a number on your phone does not prevent the caller from leaving voicemails, but most apps let you silence voicemails from blocked numbers too.
Blocking a number on iPhone
Open the Phone app and go to the "Recents" tab at the bottom. Find the number you want to block, tap the small circle with an "i" next to it, then scroll down and tap "Block this Caller." The number is now blocked — calls and texts from that number will go straight to voicemail, and you will not see a notification.
You can also block someone from your Contacts app. Open Contacts, find the person, tap "Edit" in the top right, scroll to the bottom, and tap "Block this Caller." If you want to unblock later, go back to that contact and tap "Unblock this Caller."
iPhone does not let you see a list of all your blocked numbers in one place, but you can manage them through Settings. Go to Settings > Phone > Blocked Contacts to see everyone you have blocked and unblock them if needed.
Blocking a number on Android
Open the Phone app and go to your call history. Long-press the number you want to block until a menu appears, then tap "Block number" or "Add to block list" — the exact wording depends on your phone maker. Some Android phones also let you swipe left or right on a number to reveal a block option.
If you want to block someone in your Contacts, open the contact, tap the three dots in the top right, and select "Block number." You can also block a number while a call is coming in by tapping the red decline button and selecting "Block" from the options that appear.
To see all your blocked numbers, open the Phone app, tap the three dots in the top right, go to Settings, and look for "Blocked numbers" or "Block list." The exact path varies by manufacturer — Samsung phones call it "Block list," while Google Pixel phones call it "Blocked numbers."
Using your carrier's call blocking service
Your phone company offers call blocking as a separate service from your phone's built-in blocking. Call the customer service number on your bill and ask them to block a specific number on your account. They can usually do this while you are on the phone, and the block takes effect within a few hours.
Carrier-level blocking stops the call before it reaches your phone, so you will not see a missed call notification or voicemail. This is different from blocking on your phone, where the call still reaches your phone but you do not hear it ring. Carrier blocking is more effective for persistent callers because they cannot tell whether you blocked them or if your phone is off.
Some carriers charge $3 to $5 per month for call blocking, while others include it free with certain plans. AT&T offers "Call Protect" free on some plans, Verizon includes "Call Filter" free on most accounts, and T-Mobile includes "Scam Shield" free. Ask your carrier what they offer before paying for a third-party app.
Blocking spam and robocalls with an app
TrueCaller is free and works on both iPhone and Android. It shows you the name of incoming callers even if they are not in your contacts, and it automatically blocks numbers flagged as spam by other users. You can also create a personal blocklist and set it to silent mode so blocked calls do not ring at all.
RoboKiller costs about $4 per month and uses artificial intelligence to block robocalls before they reach you. It also records fake voicemails to waste the caller's time, which can reduce the number of calls you receive over time. RoboKiller works on both iPhone and Android.
Nomorobo is free on Android and costs about $2 per month on iPhone. It blocks calls from known robocall numbers and lets you report new spam numbers to help other users. If your carrier already offers free call blocking, Nomorobo may be redundant, but it is useful if your carrier does not have a spam filter.
All three apps require permission to access your call log and contacts. Read the privacy policy before installing to understand what data they collect. Most reputable apps do not sell your data, but they do use it to improve their spam databases.
What happens when you block a number
When you block a number on your phone, the caller will hear your phone ring normally on their end, but your phone will not ring. The call goes straight to voicemail, and you will not see a missed call notification. The caller cannot tell for certain that you blocked them — they only know you did not answer.
Text messages from blocked numbers are usually hidden from your main message thread, though you can usually find them in a separate "Blocked" folder if you look for it. Some phones let you choose whether to block calls only or both calls and texts.
Blocking does not prevent voicemails. If the caller leaves a message, it will still arrive in your voicemail inbox, though many apps let you delete voicemails from blocked numbers automatically. If you want to prevent voicemails entirely, you need to use your carrier's blocking service instead.
Blocking calls from unknown numbers
If you want to block all calls from numbers not in your contacts, most phones have a "Silence Unknown Callers" or "Block Unknown" option. On iPhone, go to Settings > Phone > Silence Unknown Callers to send calls from unknown numbers straight to voicemail. On Android, open the Phone app, tap the three dots, go to Settings, and look for "Block unknown" or "Unknown caller blocking."
This setting is useful if you receive many spam calls, but it also means legitimate callers like doctors' offices or delivery services will go to voicemail. You will still see a missed call notification, so you can call them back if needed.
For more aggressive spam filtering, use a third-party app like TrueCaller or RoboKiller, which can block calls from numbers flagged as spam even if they are not in your blocklist. These apps are more effective than the phone's built-in unknown caller blocking because they use large databases of known spam numbers.
Frequently Asked Questions
Can a blocked caller tell that I blocked them?
Not for certain. When you block someone on your phone, they hear it ring normally but you do not answer. They cannot tell whether you blocked them, ignored the call, or had your phone off. Carrier-level blocking is the same from the caller's perspective.
What if I block someone by mistake?
You can unblock them anytime. On iPhone, go to Settings > Phone > Blocked Contacts and swipe left on the name to unblock. On Android, open the Phone app, go to Settings > Blocked numbers, find the contact, and tap "Unblock." They will be able to reach you immediately after you unblock them.
Do I need to pay for call blocking?
No. Your phone's built-in blocking is free, and most carriers offer free call blocking too. Third-party apps like TrueCaller are free, though some like RoboKiller charge a monthly fee. Check with your carrier first before paying for an app.
Will blocking stop robocalls completely?
No. Robocalls often come from different numbers each time, so blocking one number does not stop the next call. A third-party app with a spam database works better because it blocks numbers flagged as spam by many users, not just the ones you have personally blocked.
Can I block calls on a landline?
Yes, but only through your phone company. Call your landline provider and ask about call blocking options. Most offer a service that blocks specific numbers or all unknown callers, though the features vary by provider. Some charge a monthly fee while others include it free.