The fastest way to block robocalls right now

Most phones have a built-in call blocking feature you can turn on immediately, and it catches the majority of robocalls without you doing anything else. On an iPhone, open Settings, tap Phone, then tap Silence Unknown Callers — this sends calls from numbers not in your contacts to voicemail. On Android, open the Phone app, tap the three-dot menu, go to Settings, then tap Spam and Abuse, and turn on Filter Unknown Calls.

These built-in tools work because they block calls from numbers your phone doesn't recognize. Robocalls often come from spoofed numbers (fake caller IDs), so filtering unknown callers stops many of them before they ring. The tradeoff is that legitimate calls from doctors' offices, banks, or delivery services you don't have saved will also go to voicemail — but you can call them back if you recognize the voicemail.

If you want to keep your phone ringing for unknown numbers but block specific ones after they call, both iPhone and Android let you block individual numbers. On iPhone, open the recent call, tap the info icon, and select Block This Caller. On Android, open the Phone app, find the number in your call history, press and hold it, then tap Block Number.

Key Takeaways

  • Your phone's built-in call filter (Silence Unknown Callers on iPhone, Filter Unknown Calls on Android) stops most robocalls automatically by sending unknown numbers to voicemail.
  • You can block individual numbers after they call you by opening the call history, tapping the info button, and selecting the block option.
  • Third-party apps like Nomorobo, RoboKiller, and Truecaller offer more aggressive filtering but require you to grant them access to your call history.
  • Never give your phone number to websites or forms that ask for it unless you trust the organization, because robocalls often target numbers that appear in public databases.
  • Do Not Call registration stops telemarketing calls but not robocalls from scammers, debt collectors, or political organizations, so it is only one layer of protection.

When the built-in filter isn't enough: third-party apps

If you are still getting robocalls after turning on your phone's native filter, a third-party app can add another layer. Nomorobo, RoboKiller, and Truecaller all maintain lists of known robocall numbers and block them before they reach you. These apps work differently than your phone's filter — instead of blocking unknown numbers, they block numbers that other users have reported as spam or that match patterns typical of robocalls.

The trade-off with third-party apps is that they need permission to see your incoming calls and sometimes your contacts. Before you install one, check what permissions it asks for in the app store listing. Nomorobo and RoboKiller are available on both iPhone and Android. Truecaller works on Android and has limited features on iPhone because Apple restricts what third-party apps can do with call data.

These apps are free or low-cost, but some offer paid versions with extra features like call recording or detailed spam reports. The free versions block most robocalls effectively, so start there before paying for an upgrade.

Registering with the National Do Not Call Registry

The National Do Not Call Registry stops telemarketing calls from legitimate companies, but it does not stop robocalls from scammers, debt collectors, or political organizations. You can register your number at donotcall.gov or by calling 1-888-382-1222 from the phone you want to register. Registration is permanent — your number stays on the list until you remove it.

After you register, it takes about 31 days for telemarketing calls to drop off. If you keep getting telemarketing calls after that period, you can file a complaint on the same website. The Federal Trade Commission investigates patterns of violations, though individual complaints rarely result in action against a single company.

Do Not Call registration is worth doing because it eliminates one category of unwanted calls, but it is not a complete solution. Robocalls from scammers, IRS impersonators, or debt collectors ignore the registry entirely because they are already breaking the law.

Why you keep getting robocalls and how to reduce them

Robocalls target phone numbers that appear in public databases — online directories, warranty registrations, shopping websites, or data brokers who sell contact information. Once your number is in circulation, robocallers buy lists and dial thousands of numbers at once to find which ones are active. Each time you answer or press a button during a robocall, you confirm your number is real, and it gets sold to more robocallers.

You cannot remove your number from all databases, but you can reduce how many robocalls find you. Do not give your phone number to websites unless you trust the organization — retail sites, online forms, and free service sign-ups often sell contact data. If a website asks for your number and you are not sure why, use a different number or skip that field. Be especially cautious with warranty registration cards, online contests, and "free quote" forms, which are common sources of robocall lists.

If you answer a robocall by accident, hang up immediately without pressing any buttons. Do not press 1 to speak to a representative, do not press 2 to remove yourself from the list, and do not say anything. Pressing buttons or speaking confirms your number is active and monitored by a human, which makes your number more valuable to robocallers.

What to do if a robocall is a scam

Robocalls claiming to be from the IRS, your bank, Amazon, or Apple are almost always scams. Real organizations do not call you unexpectedly to ask for passwords, account numbers, or payment information. If you get a call like this, hang up and call the organization directly using a number from their official website or your statement — do not use a number from the caller ID, because scammers spoof real numbers.

If you have already given information to a scammer, contact your bank or credit card company immediately. If the call claimed to be from the IRS, report it to the Treasury Inspector General for Tax Administration at tigta.gov. If it claimed to be from another government agency, report it to the Federal Trade Commission at reportfraud.ftc.gov. These reports help authorities track patterns and shut down scam operations.

Do not feel embarrassed if you fell for a scam call — they are designed to sound urgent and official, and they target everyone. The important step is reporting it so others know what to watch for.

Call filtering through your phone carrier

Your phone carrier (Verizon, AT&T, T-Mobile, or another provider) offers call filtering as part of your service or for a small monthly fee. Verizon Call Filter, AT&T Call Protect, and T-Mobile Scam Shield all work similarly to third-party apps — they block numbers on known spam lists and flag suspicious calls. Some carriers include basic filtering for free and charge extra for advanced features.

Carrier-level filtering happens before the call reaches your phone, so it can be more effective than app-based blocking. The downside is that you have less control over what gets blocked — you cannot easily customize the filter or see detailed reports about blocked calls. If you want more control, a third-party app gives you more options, but carrier filtering is a good starting point if your provider offers it.

Check your carrier's website or call customer service to see what filtering options are available on your account. Many carriers have added free basic filtering in recent years, so you may already have protection turned on.

Frequently Asked Questions

Can I block all unknown callers without missing important calls?

Your phone's built-in filter sends unknown callers to voicemail, so you will not miss calls — you just will not hear them ring. Check your voicemail regularly, and if you recognize the number, you can call back. For calls you expect (doctor's office, delivery service), ask them to text you instead or add their number to your contacts before they call.

Do robocall blocking apps slow down my phone?

Third-party blocking apps use minimal battery and data because they run in the background. You may notice a slight delay when calls come in while the app checks the number against its database, but most people do not notice a difference. If your phone feels slower after installing an app, check your phone's settings to see what permissions it is using.

What if I block a number by mistake?

On iPhone, go to Settings, Phone, Blocked Contacts, and swipe left on the number to unblock it. On Android, open the Phone app, tap the three-dot menu, go to Settings, then Blocked Numbers, and tap the X next to the number you want to unblock. You can unblock numbers at any time.

Why do robocalls keep calling even after I block them?

Robocallers use spoofed numbers, so each call appears to come from a different number. Blocking one number stops that specific call, but the next robocall will come from a different spoofed number. This is why filtering unknown callers or using a third-party app is more effective than blocking individual numbers — they stop patterns of calls rather than individual numbers.

Is it safe to give third-party apps access to my call history?

Established apps like Nomorobo, RoboKiller, and Truecaller are safe and have privacy policies that explain how they use your data. Before you install any app, read the permissions it asks for and the privacy policy. If an app asks for access to your contacts, location, or photos in addition to your call history, that is a red flag — blocking apps should only need call data.