Android has built-in spam blocking that works without extra apps

Android phones come with a spam filter already turned on, but it only catches the most obvious robocalls. To block nearly all spam calls, you need to turn on a stronger setting called Filter Unknown Callers, which silences any call from a number not in your contacts. This setting lives in your Phone app, not in Settings, and takes about 30 seconds to enable.

The filter does not delete spam calls — it sends them to voicemail so you can review them later if needed. Legitimate callers you do not know will also go to voicemail, so this method works best if you mostly receive calls from people already saved in your phone. If you need to hear calls from unknown numbers, there are other blocking options that are less aggressive.

Key Takeaways

  • Filter Unknown Callers is the strongest built-in option and silences all calls from numbers not in your contacts by sending them to voicemail.
  • You turn on Filter Unknown Callers in the Phone app, not in Settings, by opening the app and finding the menu icon.
  • Google's Call Screen feature lets you see a transcript of what a spam caller is saying before you decide whether to answer.
  • If you need to hear calls from unknown numbers, you can block individual callers or use a third-party app instead of filtering all unknown calls.
  • Spam calls that pretend to be from your own number or from banks cannot be stopped by filtering alone, but reporting them helps Google improve its detection.

Turn on Filter Unknown Callers in your Phone app

Open the Phone app on your Android device. Look for three vertical dots (the menu icon) in the top right corner and tap it. You should see a menu with options including Settings. Tap Settings.

Look for an option called Spam and call screen or Block numbers — the exact name varies by phone brand and Android version. Tap it. You should see a toggle or switch next to Filter Unknown Callers. Turn it on. From that moment forward, any call from a number not in your contacts will ring once and then go to voicemail.

If you do not see this option, your phone may have an older version of Android or a different phone brand's version of the Phone app. Check your phone's main Settings app instead: go to Apps or Applications, find Phone, and look for a Spam section within that app's settings.

Use Google Call Screen to see what spam callers are saying

Call Screen is a Google feature that answers suspected spam calls for you and shows you a live transcript of what the caller is saying. You can then decide whether to talk to them, hang up, or block them. This is gentler than Filter Unknown Callers because legitimate callers still get through to you — they just have to wait a few seconds while Call Screen listens.

Call Screen is available on Pixel phones and some other Android devices. To turn it on, open the Phone app, tap the menu icon, go to Settings, then Spam and call screen, and toggle on Call Screen. When a suspected spam call comes in, you will see the transcript appear on your screen in real time. You can tap Block to add that number to your blocked list, or Allow to answer the call normally.

Call Screen requires a Google account and an internet connection to work. It also works best on newer Android versions. If you have an older phone or a non-Pixel device, this feature may not be available to you.

Block individual numbers manually

If you only want to block specific callers rather than all unknown numbers, you can block them one at a time. Open the Phone app and go to your Recent or Call History tab. Find the number you want to block, press and hold it, and tap Block number or Block. That caller will no longer be able to reach you — their calls will go straight to voicemail.

You can also block a number while a call is happening. During the call, look for a Block or Block caller button on the screen and tap it. The call will end immediately and that number will be added to your blocked list.

To see all your blocked numbers, open the Phone app, tap the menu icon, go to Settings, and look for Blocked numbers or Block list. You can unblock any number from this list if you change your mind.

Report spam calls to Google

When you block a number or decline a spam call, you have the option to report it to Google. This helps Google's spam detection system learn what spam looks like and improve its filters for everyone. Open the Phone app, go to Recent, find the spam call, press and hold it, and tap Report spam. You do not need to provide any details — just confirming that it was spam is enough.

Reporting does not remove the call from your history or undo the call itself. It only tells Google that this number is spam so the company can use that information to block similar calls in the future. The more people report a number, the faster Google can add it to its spam list.

Install a third-party spam blocking app if you need more control

If the built-in Android options do not meet your needs, you can download a third-party app from the Google Play Store. Apps like TrueCaller, RoboKiller, and Nomorobo offer more detailed blocking rules, caller ID information, and the ability to block calls based on patterns rather than just individual numbers.

Third-party apps require you to give them permission to access your call history and contacts. Read the app's privacy policy before installing it to understand what data it collects. Some apps are free with ads, while others charge a monthly fee for advanced features.

You can use a third-party app alongside the built-in Filter Unknown Callers — they work together rather than against each other. However, if you install a third-party app, you may want to turn off the built-in spam filter to avoid double-blocking and to give the app full control over what gets through.

Understand what spam blocking cannot stop

Spam calls that use spoofing — pretending to be from your own phone number, your bank, or a government agency — are harder to block because they look legitimate. Filtering unknown callers will not stop these because the number appears to be from someone you know or a trusted organization. If you get a call from your own number or from your bank asking for your password, it is almost certainly spam. Hang up and call the organization back using a number from their official website.

Some spam calls come from real phone numbers that change constantly, making it impossible to block them all individually. In these cases, your best defense is Filter Unknown Callers or Call Screen, which stops calls from numbers you have never saved. You can also report these calls to the Federal Trade Commission at reportfraud.ftc.gov, though reporting does not stop future calls to you personally.

Frequently Asked Questions

Will Filter Unknown Callers block calls from my doctor's office or delivery services?

Yes, it will. Any call from a number not in your contacts will go to voicemail, including legitimate businesses. If you expect calls from unknown numbers, save those businesses' phone numbers to your contacts before they call, or use Call Screen instead of Filter Unknown Callers so you can see who is calling before deciding whether to answer.

Can I turn off Filter Unknown Callers for certain contacts or time periods?

No, the built-in filter is all-or-nothing — it either blocks all unknown callers or none. If you need more flexibility, use Call Screen instead, which lets you decide on each call, or use a third-party app that offers scheduling or whitelist features.

What happens to calls that are filtered — are they deleted?

Filtered calls go to voicemail, not to a trash folder. You can listen to them later by opening your voicemail. If you want to permanently delete a filtered call, you can do so from your voicemail after listening to it.

Do I need a Google account to use Filter Unknown Callers?

No, Filter Unknown Callers works on any Android phone without a Google account. Call Screen, however, requires a Google account and an active internet connection to function.

Why am I still getting spam calls after turning on the filter?

Filter Unknown Callers only blocks calls from numbers not in your contacts. If a spam caller is using a number you have saved, or if they are spoofing a number you know, the call will still come through. You can block these numbers individually, or report them to Google to improve the spam detection system.