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How to Find Out an Unknown Caller’s Number

Is there a potentially shady, unknown number that keeps calling you? Besides pesky marketers, criminals also use unknown numbers to carry out scams and try to access personal data. Learn how to unmask mystery callers by revealing and tracing an unknown number. And install Avast One, a comprehensive security solution, to help prevent scams and keep your personal data private.

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Written by Deepan Ghimiray
Published on April 27, 2023

How to find an unknown caller

You can uncover an unknown caller ID by using the *69 feature code, third-party apps, or contacting your phone service provider. Unknown callers could be hiding their identity to try to scam you, so it’s important to unmask them before you fall victim.

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    Unknown callers deliberately hide their phone numbers so that no caller ID is available. Of course, sometimes regular folks who value their privacy may want to hide their number, but unknown calls and messages often come from telemarketers and scammers spreading spam or perpetrating tech support scams or malvertising ploys.

    Here’s how people can hide their phone numbers and make calls as unknown callers:

    1. Caller ID blocking: Many phone service providers give callers the option to call someone without revealing their phone number by blocking their identity from a recipient's caller ID display.

    2. Third-party apps: Some apps allow people to place calls with anonymous or fake phone numbers. Depending on the app, different technologies are used to hide a caller’s number or display virtual or disposable phone numbers.

    3. Spoofing: Caller ID spoofing enables fake information to be displayed on a recipient’s caller ID display including fake phone numbers and even different area or country codes.

    If you receive a call or message from an unknown or suspicious number, the best course of action is not to answer — at least not until you know who you’re dealing with. If you do decide to pick up, proceed with caution and don’t reveal personal information.

    Now let’s take a closer look at how to find out an unknown caller number.

    Use the *69 code to trace unknown numbers

    Dialing *69 can help trace an unknown number by activating the last-call return service. This feature provides details of the previous caller’s number and, if they’re listed in a public database, their name and address. Depending on your phone service provider, *69 may include a dial-back option allowing you to return the call and find out who called you.

    Here’s how to find an unknown caller with the *69 code:

    1. Dial *69 into your phone’s keypad. If the service doesn’t auto-activate, press the call button.

      An iPhone keypad dialing *69 to activate the last-call return service.
    2. An automated recording will tell you the last number that called you along with any other available caller ID information. Follow the last-call return service instructions to call them back, if you want.

    The *69 service is usually free, making it one of the best ways to find out an unknown caller number for free. But beware that some phone service providers do charge for last-call return services.

    Use the *57 code to trace unknown numbers

    If you receive a threatening, harassing, or suspicious call from an unknown number, dialing the *57 code automatically traces the last call you received, and alerts your phone service provider (and local law enforcement if necessary) to potential criminal activity.

    Here’s how to trace a no-caller ID number with *57:

    1. Dial *57 into the keypad of your phone and press the call button if the service doesn’t activate automatically.

      iPhone keypad dialing *57
    2. Follow the instructions provided by the voice recording, and be ready to provide more information if needed.

    3. The trace information will be sent to your service provider, along with a recording of the call. This information could be passed down to local law enforcement for further investigation.

    *57 code call tracing is usually not free, although this varies depending on your service provider. Even so, it’s probably the best course of action if you believe that you’re being targeted by scammers or fraudsters.

    Contact your service provider

    Another way to find no-caller ID numbers is to contact your service provider’s customer support line directly and ask them about their call tracing services. Each service provider offers different services, but they might know how to find out an anonymous number that *69 can’t trace, and they can usually even tell you exactly how they are hiding their real number.

    Of course, these services usually come with a fee, so make sure you know what the costs are before you proceed.

    Use a third-party app or service

    Third-party apps can find an unknown number using a variety of methods, but usually they perform a reverse phone lookup, which scrapes information from public databases, social media platforms, and other online sources to give you details that can help identify an unknown number.

    Let’s take a look at some of these apps and services:


    TrapCall is an Android and iOS app that intercepts calls from unknown numbers and redirects them to their servers. TrapCall uses software analysis to reveal the caller’s identity. Besides unmasking unknown callers, TrapCall has other features that let you block spammers, blacklist unwanted numbers, and transcribe voicemails into text.

    Do a reverse lookup with Spokeo

    Spokeo is a people search website that collects data from online and offline sources. Along with helping people reconnect with old friends or research potential business partners and employees, it has a reverse lookup feature that lets you look up unknown numbers and find the caller’s name, address, social media profiles, and more. This helps verify the identity of someone you’ve spoken to, but it won’t reveal a number hidden by caller ID blocking.


    TrueCaller is an app that uses a crowdsourced directory of phone numbers and caller information to help you identify the name and address of an unknown caller by matching incoming calls with a directory of known numbers, compiled from both user submissions and public records. You can also use it to automatically block incoming calls from numbers known to be used by scammers or spammers.


    BeenVerified is an online background-check service that lets you verify people and businesses. Its extensive sources are compiled from public and private databases. If you have an unknown caller’s phone number, run it through BeenVerified to possibly reveal their name, address, social media profiles, and other information.

    Report scam calls to the FTC (for US citizens)

    The Federal Trade Commission (FTC) is an independent US government agency responsible for protecting consumers from unfair and deceptive market practices, including fraud and scams. If you’re a victim of a scam call, the FTC can investigate and possibly prosecute the scammers — even if they used an unknown caller ID.

    Reporting scams to the FTC — or your local equivalent if you live outside the US — also helps them build up an in-depth picture of the scam landscape to find patterns and trends, and develop strategies for identifying and stopping future scams before they occur.

    Here’s how to report a scam to the FTC:

    1. Go to the FTC’s fraud report page.

    2. Click Report Now and fill out the form with as many details as you can provide.

    3. Click Submit when you’re done to file your report with the FTC.

    And remember, the FTC can help stop phone spoofing and other phone-related crimes and malpractices, but you can also report internet scams and other forms of fraud to them, too.

    Use your phone settings to silence unknown callers

    Although there are no built-in tools to reveal no caller ID on iPhone or Android phones, if you’re more interested in stopping harmful calls than finding out who called you, you can black unknown callers altogether through your phone settings.

    Here’s how to silence unknown callers on an iPhone:

    1. Open Settings and tap Phone.

    2. Toggle on Silence Unknown Callers.

      iPhone's Phone settings, highlighting the Silence Unknown Callers feature.

    And while you’re at it, boost your security further and shut down other avenues of attack used by scammers and hackers with these essential iPhone safety tips.

    It’s also quick and easy to silence unknown callers on Android. Here’s how:

    1. Open the Phone app, tap the three-dot menu icon in the top-right corner, and select Settings.

       Accessing Android phone settings menu.
    2. Tap Blocked numbers and toggle on Block unknown callers or Block calls from unidentified numbers.

      Enabling call blocking for unknown numbers in Android phone call settings.

    Silencing unknown callers can help you block spam calls and stop spam text messages. And it can also block legitimate calls from callers who choose to use an unknown number. If you think you’re missing out on important calls, turn this feature off by following the steps above and moving the toggle switch to the off position.

    Keep unknown callers out with Avast

    All the personal data stored on your phone can make it a tempting target for cybercriminals, scammers, and snoops. That’s why using a robust online privacy and security tool like Avast One is so important, because it can help prevent scams and other threats.

    Built on top of an award-winning, machine-learning threat detection engine, and packed with features like a built-in VPN, Avast One protects your device with a powerful array of tools. Get real-time protection against malicious software, suspicious links and downloads, and dangerous websites. Install Avast One for free today and start protecting your digital life right now.

    Fight scams, block malware, and prevent threats with Avast One

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    Deepan Ghimiray