How to Block Unwanted Calls: 8 Proven Methods to Stop Spam, Robocalls & Unknown Numbers

Stop spam, robocalls, and unknown numbers with these 8 proven methods to block unwanted calls and protect your phone from interruptions.

Unwanted calls—from robocalls to spam callers—have become a daily nuisance for millions. According to Federal Communications Commission (FCC) data, consumers report over 228 million robocalls every month. Whether it’s a persistent telemarketer, a fraudulent scammer, or simply an unknown number you don’t recognize, there are effective ways to block spam calls, filter unknown callers, and regain control of your phone.

Introduction

Unwanted calls not only disrupt your day but can also pose security risks. Robocalls that spoof legitimate numbers, phishing attempts disguised as missed connections, and relentless marketing calls all fall under “unwanted calls.” The rise of AI-powered robocalling systems has only exacerbated the problem: call volume jumped 31% year-over-year in 2024.

How to Check if a Phone Number Is Spam

Before blocking a caller, it helps to verify whether the number is truly spam. These call-screening techniques can save you from accidentally blocking legitimate contacts.

Online Lookup Tools

Truecaller Reverse Lookup: Enter the phone number on Truecaller’s website or app to see community-reported spam labels.

Free Reverse-Phone Lookup Sites: Websites like WhoCallsMe.com and SpyDialer aggregate user complaints and caller ID data.

Caller-ID & Reverse-Lookup Apps

Built-in Android Spam Warnings: Android’s Phone app highlights suspicious calls with a “Spam?” label and real-time alerts.

Hiya & Whoscall: These apps integrate with your dialer to identify spam callers in real time before you answer.

Built-in Phone Features

iPhone’s Silence Unknown Callers: Automatically mutes calls from numbers not in your Contacts or recent calls—and sends them to voicemail.

Android’s Spam Protection: Go to Phone App → Settings → Spam and Call Screen to enable caller ID and block suspected spam.

Block Calls via Your Phone’s Settings

Smartphone settings provide the easiest, no-cost way to block individual numbers or filter all unknown callers.

Block Individual Unknown Callers

On iPhone
1. Open the Phone app and navigate to Recents, Contacts, or Voicemail.
2. Tap the ℹ️ icon next to the number.
3. Scroll down, tap Block this Caller, then Block Contact.
On Android
1. Open the Phone app and go to Recents.
2. Tap the ℹ️ icon next to the number.
3. Tap Report (if available), choose the spam category, then tap Block.

Block spam calls one by one for telemarketers or repeat offenders without affecting unknown callers you wish to hear from.

Stop All Unknown or Private Numbers

iPhone: Silence Unknown Callers
1. Go to Settings → Phone → Silence Unknown Callers.
2. Toggle On.
  Only numbers saved in your Contacts or recently called will ring; all others go straight to voicemail.
Android: Caller ID & Spam Protection
1. In the Phone app, tap ⋮ → Settings → Spam and Call Screen.
2. Enable Caller ID & spam protection, then under Block numbers, toggle Block spam and scam calls.

This blocks private and unidentified numbers, reducing nuisance calls—though you may miss legitimate calls from new contacts or delivery services.

Samsung Smart Call Scanner

Samsung’s One UI integrates Smart Call to detect and warn about spam.

Open Phone → ⋮ → Settings → Block numbers.
Toggle Block calls from unknown numbers.

Smart Call uses both Samsung’s database and Google’s caller ID to flag suspicious callers.

Use Dial-In Blocking Codes

For those with landlines or who prefer carrier-level blocking, dial codes offer a quick solution.

*Dial 77: Blocks all calls without a Caller ID on most landlines and some mobile carriers. An automated prompt confirms activation; dial *87 to disable.

*Dial 61: On AT&T home phones, this blocks the most recent incoming call. You must dial *61 immediately after the unwanted call; AT&T allows up to 100 numbers in the block list.

Dial #662#: Activates T-Mobile’s Scam Block feature on compatible mobile plans. Suspicious/scam calls are filtered and never reach you. To deactivate, dial #632#.

These MMI (Man-Machine Interface) codes run at the carrier level, ensuring spam calls never reach your device.

Register on the Do Not Call Registry

The National Do Not Call Registry stops legitimate telemarketing calls—though it won’t block scammers or political outreach.

Call 1-888-382-1222 (voice) or 1-866-290-4236 (TTY) from the number you wish to register.
Or sign up online at NationDoNotCall.gov.
Enter up to three phone numbers and your email; confirm via the email link within 72 hours.

Registration is free and takes effect within 31 days. Once on the registry, most telemarketers must cease calling or face fines—making it an essential tool to prevent unwanted calls from legitimate marketing outfits.

Best Call-Blocking Apps (Android & iOS)

For more advanced protection, dedicated call-blocking apps offer features like community reporting, SMS filtering, and automatic updates.

Phone by Google (Android)

Built-in in Pixel and many Android phones.
Caller ID & spam filter flags and blocks suspected spam.
Note: Call history (including blocked calls) may sync with Google for “safety improvements.”

Truecaller (Android & iOS)

Community-driven spam list with over 350 million users.
Auto-block top spammers and create custom blocklists.
Caller ID displays names for unknown numbers.

UnknownPhone (Android & iOS)

Free spam database with geolocation-based blocking.
Block by area code or country; whitelist trusted numbers.
Access the largest U.S. spam directory via Unknownphone.com.

AT&T ActiveArmor℠ (AT&T Customers)

Network-level fraud blocking and spam warnings.
Automatic updates via AT&T’s database.
Customize block/unblock lists in the app.

Showcaller (Android & iOS)

Billion-number database with real-time spam detection.
Caller ID and community spam reports.
Lightweight app with easy setup.

YouMail (Android & iOS)

Plays “number disconnected” greeting to blocked callers.
Visual voicemail interface for spam calls.
Auto-text follow-up that redirects callers to your personal landing page.

Each app brings unique advantages—from network-level protection (ActiveArmor) to social-powered blacklists (Truecaller). Try a combination for maximal coverage.

Top Free Spam-Blocking Apps for Android

If you prefer solely free solutions on Android, these apps earn high marks for spam call blocking, SMS filtering, and user-friendly features:

Truecaller
- Powerful dialer with call & SMS blocking.
- Custom blacklist and community spam list.
Call Control – Call Blocker
- Community IQ to auto-block robocalls.
- Do Not Disturb mode and enhanced caller ID.
Hiya – Caller ID & Block
- Real-time identification of unknown callers.
- Automatic spam detection; SMS scan integration.
Whoscall – Caller ID & Block
- Smart spam detection with personalized Whoscall card.
- Offline database to identify calls without data.
Mr. Number – Block Calls & Spam
- Block by individual, area code, or country.
- Report spam to warn the community.

These free call-blocking apps balance robust features with zero cost, making them ideal for anyone looking to block unwanted calls permanently.

Conclusion & Best Practices

Blocking unwanted calls is an ongoing battle. For maximum protection:

Combine approaches: Use built-in settings, dial-in codes, and apps together.
Review blocklists: Periodically check blocked numbers to avoid missing important calls.
Stay updated: Keep your OS, carrier features, and call-blocking apps updated to leverage the latest spam filters and Caller ID databases.
Be vigilant: Scammers adapt fast. Never share personal information over the phone unless you verify the caller’s identity independently.

By following these methods—whether you choose to block individual spam calls, silence all unknown callers, register on the Do Not Call Registry, or enlist powerful call-blocking apps—you’ll greatly reduce interruptions, stop robocalls, and reclaim your peace of mind.

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