The fastest way to stop scam calls is to use your phone's built-in tools, then add a call-blocking app if the calls keep coming

Your phone already has a way to block numbers. On iPhone, open the Phone app, find the number in your recent calls or voicemail, tap the info icon, and select "Block this Caller." On Android, open the Phone app, press and hold the number, and tap "Block number." These built-in blockers stop calls from that specific number, but scammers rotate numbers constantly, so blocking one does almost nothing.

The real solution is a call-blocking app that recognizes patterns — not just individual numbers. These apps compare incoming calls against databases of known scam numbers and flag suspicious calls before they ring. Some are free; others cost a few dollars per month. The trade-off is that they see your incoming calls to do this work, which is why privacy matters when you pick one.

Key Takeaways

  • Block individual numbers through your phone's built-in settings, but expect this alone to stop only a small fraction of scam calls since scammers use new numbers constantly.
  • Call-blocking apps like RoboKiller, Nomorobo, and Whoscall use databases of known scam patterns and can filter calls before they reach you, though they do see your incoming call data.
  • Your phone carrier (Verizon, AT&T, T-Mobile, etc.) offers free or low-cost call-filtering services that work at the network level before calls even reach your phone.
  • Do not answer calls from numbers you do not recognize, and never give personal information, passwords, or payment details to an unsolicited caller, even if they claim to be from your bank or the government.
  • Report scam calls to the Federal Trade Commission at reportfraud.ftc.gov so the data helps improve blocking tools for everyone.

Use your carrier's built-in call filter first

Verizon, AT&T, T-Mobile, and most other carriers offer call-filtering services that work before calls reach your phone. These are often free or cost $3 to $5 per month. The filter runs on the carrier's network, not on your phone, so it catches calls before they consume your battery or interrupt you.

Verizon calls theirs Call Filter. AT&T offers Call Protect. T-Mobile has Scam Shield. Check your carrier's website or call customer service to turn on the free version — many customers do not know it exists. The free tier usually blocks obvious spam and robocalls. Paid tiers add features like blocking calls from numbers not in your contacts or letting you see who called before you answer.

These carrier filters are a good starting point because they work on the network level and do not require you to install anything. The downside is that they are less aggressive than third-party apps — they catch the most obvious scams but miss more sophisticated ones.

Add a third-party app if carrier filtering is not enough

RoboKiller uses artificial intelligence to learn what scam calls sound like and blocks them in real time. It costs about $4 per month. The app can also answer calls with a bot that wastes the scammer's time, though this feature is polarizing — some people find it satisfying, others find it unsettling. RoboKiller sees your incoming calls to do its work.

Nomorobo is free on iPhone and costs about $2 per month on Android. It maintains a crowdsourced database of scam numbers and blocks calls that match known patterns. Nomorobo also works at the carrier level on some networks, which means it can block calls before they reach your phone at all. It is simpler than RoboKiller and does not use artificial intelligence, just pattern matching.

Whoscall is free with ads or about $3 per month without them. It identifies incoming numbers and flags likely scams. Whoscall also works internationally, so it is useful if you receive calls from outside the United States. Like the others, it sees your call data to function.

All three apps require permission to access your phone's call history and contacts. Before you install one, read what data it collects and where it stores it. Look for apps that say they do not sell your data to third parties. Check the app store reviews — if many users report that calls are still getting through, the app may not be worth the cost.

Understand the privacy trade-off of call-blocking apps

Any app that blocks scam calls has to see your incoming calls to do its job. This means the app knows who is calling you, when, and how often. Most reputable call-blocking apps say they do not sell this data, but they do use it to improve their scam databases. Read the privacy policy before you install.

Carrier-level filtering (Verizon Call Filter, AT&T Call Protect, T-Mobile Scam Shield) has a smaller privacy footprint because the filtering happens on the carrier's network, not on your phone. Your carrier already knows who is calling you — that is how phone networks work — so using the carrier's own filter does not expose you to a new company.

If privacy is your main concern, use your carrier's free filter and block individual numbers manually. This approach stops fewer scam calls but does not require you to trust a third-party app with your call history.

Do not answer calls from unknown numbers

The most reliable way to avoid scam calls is to not answer them. If you do not recognize the number, let it go to voicemail. Real callers — your doctor, your bank, your employer — will leave a message. Scammers usually hang up.

If you do answer and realize it is a scam, hang up when ready. Do not stay on the line to argue or ask questions. Do not press buttons to "remove yourself from the list" — that tells the scammer your number is active and monitored, and they will call more often.

Never give personal information to an unsolicited caller, even if they claim to be from your bank, the IRS, or Social Security. Real government agencies and banks do not call you out of the blue asking for passwords, Social Security numbers, or payment information. If you are unsure, hang up and call the organization back using the number on your bill or their official website.

Report scam calls to help others

When you receive a scam call, report it to the Federal Trade Commission at reportfraud.ftc.gov. The FTC does not investigate individual cases, but the data you provide helps identify patterns and informs law enforcement. It also helps call-blocking apps improve their databases.

You can also report scam calls to your state's attorney general office. Many states have a consumer protection division that tracks scams in your area. Reporting does not stop the call you already received, but it contributes to the larger effort to shut down scam operations.

If a scam caller claims to be from a real company — your bank, Amazon, Apple — report it to that company as well. They want to know when scammers are impersonating them, and the report helps them warn other customers.

Recognize common scam call patterns

Scammers often use the same tactics. If a caller says you have won a prize you did not enter, your account has been compromised, or you owe money to the government, it is almost certainly a scam. Legitimate organizations do not contact you by phone to demand when ready payment or personal information.

Scammers also use caller ID spoofing — they make their call appear to come from a number you recognize, like your bank or a local business. This is why you should never trust caller ID alone. If the call seems urgent, hang up and call the organization back using the number on your statement or their official website.

Another common tactic is the "one-ring scam" — a scammer calls once and hangs up, hoping you will call back. Calling back connects you to an international number that charges you a premium rate. If you do not recognize the number, do not call it back.

Frequently Asked Questions

Can I block all unknown numbers at once?

Yes, most phones have a setting to silence calls from unknown numbers. On iPhone, go to Settings > Phone > Silence Unknown Callers. On Android, open the Phone app, tap More > Settings > Spam and Call Screen, and turn on "Filter Unknown Calls." This sends unknown numbers to voicemail, but you may miss legitimate calls from new contacts or businesses.

What if a scammer is using my own number?

Caller ID spoofing makes it look like the call is coming from your number. You cannot block your own number, but you can tell people it is a scam. If someone calls you saying they are from your number, hang up and report it to the FTC. Your phone company cannot stop spoofing entirely, but call-blocking apps can flag these calls as suspicious.

Do I have to pay for call blocking?

No. Your carrier offers free call filtering, and apps like Nomorobo are free on iPhone. Paid apps add features like real-time AI blocking or ad-free use, but the free versions stop most common scams. Start with your carrier's free filter before spending money.

Will blocking scam calls stop them completely?

No. Scammers rotate phone numbers constantly, so blocking one number stops only that one caller. Call-blocking apps reduce the number of scam calls you receive by recognizing patterns, but they cannot stop all of them. The combination of carrier filtering, a third-party app, and not answering unknown numbers is the most effective approach.

What should I do if I already gave information to a scammer?

Contact your bank and credit card companies when ready and tell them what information was compromised. Ask them to monitor your accounts for fraud. Place a fraud alert with the three credit bureaus (Equifax, Experian, TransUnion) by visiting annualcreditreport.com. Report the scam to the FTC at reportfraud.ftc.gov and to your state's attorney general.