How to Block Spam Calls on iPhone, Android, and Your Carrier
By Nathan Cole, fraud analystUPDATED 06/26Block one specific number first (iPhone and Android)
When a single number keeps calling, blocking that exact number is the quickest win. It stops that one caller cold, though it will not stop the next spoofed number. Start here, then add the broader filters in the sections below.
On iPhone:
- Open the Phone app and tap Recents.
- Tap the small information (i) icon next to the number you want gone.
- Scroll to the bottom and tap Block this Caller.
- Confirm by tapping Block Contact. The number can no longer call or text you.
On Android (Google Phone, Samsung, and most others):
- Open the Phone app and tap Recents.
- Press and hold the number you want to block.
- Tap Block / report spam (wording varies slightly by phone).
- Confirm. On Samsung you can also go to Settings > Block numbers to add numbers by hand.
If you want to know who was behind the number before you decide, our guide on who called me from this number shows how to check it for free.
Turn on Silence Unknown Callers (iPhone)
Blocking one number at a time is slow when spammers rotate through dozens of them. iPhone has a built-in switch that sends every caller who is not in your contacts straight to voicemail. Your phone does not ring, and you see the call in Recents so you can call back anything real.
- Open Settings.
- Scroll down and tap Apps, then Phone (on older iOS, tap Phone directly).
- Tap Silence Unknown Callers.
- Toggle it on.
One honest caveat: this also silences first-time calls from a new doctor, delivery driver, or a job interview where the number is not saved yet. Check your Recents and voicemail once a day so you do not miss something that matters. If that trade-off feels too aggressive, lean on the carrier filter in the next section instead.
Use your phone's built-in spam filter (Android)
Most Android phones can flag suspected spam automatically using Google's caller ID database, so junk calls are labeled or silenced before you ever pick up. This is free and built in. Turn it on like this:
- Open the Phone app and tap the three-dot menu in the corner.
- Tap Settings, then Caller ID & spam (Samsung calls it Caller ID and spam protection).
- Turn on See caller and spam ID.
- Turn on Filter spam calls so flagged calls go to voicemail silently.
Samsung users can also open Phone > Settings > Block numbers and switch on Block unknown/private numbers for an extra screen. None of this is perfect, but it cuts the obvious robocalls without you lifting a finger. When a call still gets through and you are not sure about it, run it past our is this number a scam checklist before you call back.
Add your carrier's free call-blocking app
Your phone company runs spam detection at the network level, which can stop calls before they even reach your handset. The major US carriers offer this free, and it stacks nicely on top of your phone's own settings. Here is what each one provides.
| Carrier | Free tool | What it does |
|---|---|---|
| Verizon | Call Filter | Spam detection, auto-block high-risk calls, spam reporting |
| AT&T | ActiveArmor | Automatic fraud blocking, spam labels, personal block list |
| T-Mobile | Scam Shield | Scam ID and Scam Block, free Proxy number, caller ID |
Search your carrier's name plus the app in your app store, install it, and sign in with your phone number. The free tier is enough for most people. Each carrier also sells a premium version (caller ID on every call, reverse lookups, personal spam controls), but you can skip it. If you ever do compare paid background-check tools, read how accurate reverse phone lookups really are first so you know what you are paying for.
Third-party apps: useful, but read the fine print
Apps like Truecaller, Hiya, and Nomorobo maintain large community-reported spam lists and can catch numbers your carrier misses. They work as a third layer if your phone and carrier filters are not enough. A few things to weigh before you install one:
- They want access to your contacts and call log. Read the permissions. Some apps upload your address book, which is how their database grows.
- Free versions are limited. The genuinely useful blocking often sits behind a monthly fee, so check the price before you commit.
- They are not flawless. No app blocks everything, and they sometimes flag a legitimate caller as spam.
For most readers, the built-in iPhone or Android filter plus a free carrier app handles the problem without sharing your contacts with anyone. Reach for a third-party app only if you are still drowning in junk after that. For the bigger picture on cutting your call volume, see our companion guide on how to stop spam calls.
Report and register to slow the flow
Blocking handles the calls you already get. Reporting helps shut down the operations behind them and keeps your number off easy lists. These steps are free and take a few minutes.
- Register with the National Do Not Call Registry at donotcall.gov. It will not stop scammers, who ignore the law, but it cuts legitimate telemarketing within 31 days.
- Report unwanted calls to the FTC at reportfraud.ftc.gov, and report illegal robocalls or spoofing to the FCC at fcc.gov/complaints.
- Report the number in your phone using the Block / report spam option. That feedback trains the carrier and Google databases that protect everyone.
- Never press a button to opt out during a robocall. Pressing 1 or 2 confirms your number is live and usually brings more calls, not fewer.
If a call left you rattled or asked for money, our pages on how to find out who called you and the best reverse phone lookup options walk through identifying the caller safely.
Frequently asked questions
Will blocking a number stop all spam calls from that scammer?
No. Blocking stops that exact number, but most spam operations spoof a different caller ID for each call, so a new number can still ring through. Pair number-blocking with Silence Unknown Callers on iPhone or your phone's spam filter on Android, plus a free carrier app, to cover the rotation.
Does Silence Unknown Callers send real callers to voicemail too?
Yes, and that is the trade-off. Any caller who is not in your contacts, including a new doctor, delivery driver, or job interviewer, goes straight to voicemail without ringing. The call still shows in Recents, so check it once a day. If you cannot risk missing first-time callers, use the carrier filter instead, which targets known spam more narrowly.
Do I need to pay for a spam-blocking app?
For most people, no. The blocking built into iPhone and Android, combined with your carrier's free app (Verizon Call Filter, AT&T ActiveArmor, or T-Mobile Scam Shield), handles the bulk of junk calls at no cost. Paid apps and premium carrier tiers add features like full caller ID and reverse lookups, but they are optional, not necessary.
Should I answer and press a button to be removed from the list?
Never press a button during a robocall to opt out. On an illegal robocall, pressing 1 or 2 simply confirms your number is active and reaches a real person, which usually triggers more calls. Hang up, then block and report the number instead.
What is the difference between blocking and reporting a number?
Blocking stops that number from reaching your phone again. Reporting sends the number to your carrier, Google, the FTC, or the FCC so it can be flagged in shared databases that protect everyone. Doing both is best: block to protect yourself now, report to help slow the operation down.
How do I block calls from unknown or private numbers entirely?
On iPhone, turn on Silence Unknown Callers under Settings then Phone. On Samsung Android, open Phone then Settings then Block numbers and switch on Block unknown/private numbers. On Google Phone, use Caller ID and spam to filter flagged calls. Just remember this also screens first-time legitimate callers, so review your voicemail regularly.
Former fraud investigator. Runs the same set of known numbers through every service to score real accuracy, and always shows the free way to ID a caller first. How we review →