How to Block Unknown Calls on Android

Spam calls and unknown numbers are a plague that seems never-ending. I get at least 3-4 calls per week from numbers I don’t recognize, and most are sales attempts, scams, or robocalls. Fortunately, Android offers several ways to block these calls, and in this article I’ll explain all the options from the simplest to the most advanced.

Table of contents

How to block unknown calls on stock Android (Pixel)

Google Pixels have an excellent built-in feature for managing unknown calls:

1. Open the Phone app.
2. Tap the three dots (⋮) in the top right corner.
3. Go to Settings > Spam and Call Screen.
4. Toggle “Filter spam calls” on.
5. To completely block unknown numbers, enable “Block unknown numbers.”

Google Pixel also has “Google Call Screen”, which answers calls for you and shows a real-time transcription. It’s impressive: the assistant asks the caller the reason for the call and you decide whether to answer or not.

To enable Call Screen:

1. Open the Phone app > Settings.
2. Tap Caller ID & spam.
3. Enable “See caller and spam ID.”
4. Configure your preferred automatic responses.

Pro-tip: Google Call Screen is one of the best Pixel features. If you’re considering a new Android phone, this single feature alone is worth it.

How to block unknown calls on Samsung

Samsung has its own anti-spam tools in One UI:

1. Open the Phone app.
2. Tap three dots (⋮) > Settings.
3. Go to Block numbers.
4. Toggle “Block unknown callers” or “Block hidden numbers” on.

Samsung also offers “Smart Call”, which identifies spam calls before you answer:

1. Go to Settings > Apps > Default apps > Phone app.
2. Make sure “Samsung Phone” is selected.
3. In the Phone app, go to Settings > Caller ID and spam protection.
4. Toggle “Caller ID and spam protection” on.

Smart Call shows the company name or marks the call as spam before you answer. It’s not perfect, but it filters most annoying calls.

How to block calls on Xiaomi/Redmi/POCO

On MIUI/HyperOS, call management is quite complete:

1. Open the Phone app.
2. Tap three dots (⋮) > Settings.
3. Go to Blocklist.
4. Toggle “Block unknown numbers” on.
5. You can also add specific numbers to the blacklist.

Xiaomi has its own built-in caller ID:

1. In the Phone app, go to Settings > Caller ID.
2. Enable the feature to identify spam and business calls.

If Xiaomi’s native feature isn’t enough, “Truecaller” works great on MIUI and has a massive database of known spam numbers.

Recommended apps for blocking spam calls

If your Android’s native feature isn’t sufficient, these are the best apps for blocking unwanted calls:

Truecaller

Truecaller is the most popular app for identifying and blocking spam calls. It has a database of billions of numbers and can identify who’s calling even if you don’t have the number saved.

What I love about Truecaller is that it works as a replacement for your default phone app, showing the caller’s name in real time. It’s free with ads or $4.99/month ad-free.

Hiya

Hiya is another excellent app, especially in the US. It identifies spam, scams, and fraudulent calls. It has fewer ads than Truecaller and the interface is cleaner.

Should I Answer?

This app is best for privacy. It doesn’t need access to your contacts and works with a community database of numbers reported as spam. It’s completely free with no ads.

Google Phone (for all Androids)

If your Android doesn’t come with Google’s Phone app, you can download it from the Play Store on many devices. It comes with built-in spam filtering and works very well.

How to block a specific number on any Android

If you’ve already received a call from a number you want to block, the process is straightforward on most Androids:

1. Open the Phone app.
2. Go to the Call history or Recents tab.
3. Tap the number you want to block.
4. Look for “Block” or “Report as spam” option.
5. Confirm the block.

On some Android phones, blocking a number will ask if you want to report it as spam. Always do this: you’re helping other people be warned about that number.

Warning: When you block a number, that person won’t know they’re blocked. They’ll hear a busy tone or be redirected to voicemail depending on your settings. Make sure you don’t accidentally block important numbers.

How to block calls from hidden numbers

Calls from hidden numbers are especially annoying because you can’t identify or block them individually. Fortunately, Android allows blocking them all at once:

On most Androids:

1. Open Settings > Apps > Phone.
2. Go to Call blocking.
3. Enable “Unknown” or “Private number.”

On Samsung:

1. Phone app > Settings > Block numbers.
2. Toggle “Block hidden numbers” on.

On Xiaomi:

1. Phone app > Settings > Blocklist.
2. Toggle “Block unknown numbers” on.

Keep in mind that blocking hidden numbers will also block legitimate calls from services that hide their number, like some doctors or public institutions.

What to do when spam calls come from your own carrier

One of the most frustrating problems is that sometimes spam calls come from your own phone company. They call to offer promotions, switch plans, or survey your satisfaction. Blocking these numbers can be counterproductive because you might block legitimate customer service calls.

How to handle it

1. Register on the Do Not Call list: In the US and many other countries, there’s an advertising exclusion registry. By registering, companies are legally required to stop calling you for commercial purposes. It’s free and very effective.
2. Ask your carrier to exclude you from campaigns: Call customer service and explicitly request they don’t contact you with promotional offers.
3. Use filtering instead of blocking: Rather than completely blocking your carrier’s numbers, use Google Call Screen or Truecaller to filter and decide in real time whether to answer.

Numbers you should never block

Be careful about blocking numbers that could be important:

• Your bank’s numbers: For security notifications or fraud alerts.
• Medical centers: For appointment confirmations or test results.
• Emergency services: Although it’s unlikely they’d call from a hidden number.
• Your own carrier: For service outage notices or technical issues.

Pro-tip: Before blocking a number, Google it. There are websites like “Who Called Me” or community databases that tell you if it’s spam or a legitimate number. Spend 10 seconds investigating before you block.

FAQ: Frequently Asked Questions

Does call blocking affect SMS?

No, call blocking generally doesn’t affect text messages. To block spam SMS, you need to configure it separately in the Messages app or use a third-party app like Truecaller.

Can I see blocked calls?

Yes, all Android phone apps keep a record of blocked calls. You can access this record from Settings > Block numbers > Log or Block list.

Does the blocked person know they’re blocked?

No. The person will hear a busy tone or be redirected to voicemail, but won’t receive any notification that they’re blocked.

Does blocking work with WhatsApp and other apps?

No, system call blocking only affects phone calls. For WhatsApp, Telegram, and other apps, you need to block contacts individually within each application.

Conclusion

Blocking unknown calls on Android is easier than it seems and the result is immediate. From the native options on Samsung, Xiaomi, or Google to apps like Truecaller, you have plenty of tools at your disposal. My recommendation: enable blocking for unknown numbers and try Google Call Screen if you have a Pixel. In less than a minute of setup, your spam calls will almost completely disappear.