Blacklist Number: How to Block a Number on Android and iPhone

Unwanted calls can interrupt your work, family time or sleep. If one number keeps calling, you can add it to your phone’s block list. This is often called blacklisting a number.

The block list is useful when you want to stop calls from a specific number. It works differently from spam filtering and DND preferences, though. This guide explains what happens when you block a number, how to block or unblock it on Android, Samsung Galaxy and iPhone, and what you can do about promotional or suspected fraud calls in India.

What Does It Mean to Blacklist a Number?

To blacklist a number means to add it to your phone’s blocked list. Your phone then handles calls from that number according to its settings. The call may be declined or silenced, but the exact behaviour can vary by device and network.

Blocking a number may not block every way that person can contact you. For example, blocking them in your Phone app may not stop messages on WhatsApp. You may need to block them separately in each app.

Also, if a caller starts using a different number, blocking the original number won’t affect the new one.

Blocking, Spam Filtering and DND: How Are They Different?

These features can all help you manage unwanted calls, but each works differently. Use blocking for a specific caller, spam filtering for calls flagged as suspicious, and DND when you want to silence calls or notifications.

Option	What it does	Best used for	What it may not do
Block a number	Adds a selected number to your phone’s block list.	Stopping repeated calls from one number.	It may not block calls from the same person using another number or app.
Spam filtering	Flags, silences or filters calls that your phone or service provider identifies as possible spam.	Managing calls from numbers you haven’t blocked yourself.	It may not catch every spam call. Check your spam or filtered call list in case an expected call appears there.
TRAI DND preference	Lets you register a preference to reduce promotional commercial communications through your telecom provider.	Reducing promotional calls and messages.	It does not block every unknown or suspected fraud call. TRAI’s BLOCK PROMO option excludes service, transactional and government communications.
Phone’s Do Not Disturb mode	Silences calls and notifications according to the settings and exceptions you choose.	Quiet hours, meetings or times when you don’t want interruptions.	It may silence calls without blocking the number. The call could still appear in your call history.

In short: Blocking manages a specific number on your phone. Spam filtering helps identify possible spam, while TRAI preferences apply to promotional commercial communications. Your phone’s Do Not Disturb mode silences interruptions based on your settings.

How to Block a Number on Android

Menu names may vary by phone model, Android version and Phone app.

Using the Google Phone App

1. Open the Phone app.
2. Tap Recents.
3. Select the call from the number you want to block.
4. Tap Block / report spam.
5. Confirm your choice. Reporting the number as spam is optional.

To add a number that isn’t in your call history:

1. Open the Phone app.
2. Tap More > Settings > Blocked numbers.
3. Tap Add a number.
4. Enter the number and confirm.

On a Samsung Galaxy Phone

To block a recent caller:

1. Open the Phone app.
2. Tap Recents.
3. Select the number, then open its details.
4. Tap Block and confirm.

To add a number manually:

1. Open the Phone app.
2. Tap More options > Settings > Block numbers.
3. Enter the number.
4. Tap Add.

Does Android Call Blocking Also Block Text Messages?

Not always. Call and text blocking may use separate settings on Android. If the number can still message you:

1. Open your Messages app.
2. Open the conversation with that number.
3. Find and select the app’s Block option.
4. Confirm your choice.

Samsung Messages may have its own controls for blocking conversations.

How to Block a Number on iPhone

1. Open the Phone app.
2. Tap Recents.
3. Tap the Info button next to the number.
4. Scroll down and tap Block Caller.
5. Confirm your choice.

On iOS 26, review your blocked contacts under Settings > Privacy & Security > Blocked Contacts. On older iOS versions, check under Settings > Phone > Blocked Contacts.

How to Unblock a Number

Google Phone

1. Open the Phone app.
2. Tap More > Settings > Blocked numbers.
3. Select the number.
4. Tap Unblock.

Samsung Galaxy

1. Open the Phone app.
2. Tap More options > Settings > Block numbers.
3. Find the number.
4. Tap the minus sign beside it.

iPhone

1. Open Settings.
2. Go to Privacy & Security > Blocked Contacts on iOS 26. On older versions, go to Phone > Blocked Contacts.
3. Edit the list.
4. Remove the contact.

After unblocking a number, future calls or messages may reach you again. If the person contacts you through another app, check that app’s block list too. Menu names may vary by phone model and software version.

How to Reduce Promotional Calls in India

Blocking one number won’t stop every promotional call, especially if calls come from different numbers. You can also register a preference to reduce promotional commercial communications.

TRAI lists BLOCK PROMO as an option for blocking promotional commercial communications across categories. Send BLOCK PROMO by SMS to 1909, or dial *1909*50#. This preference excludes service and transactional communications, as well as government communications. It does not block every unknown or suspected fraud call. 

For more information, read our guide to activating DND on Jio, Airtel, Vi and BSNL.

How to Report Suspected Fraud Calls

If a call or message appears to be part of a suspected fraud, you can report it through Chakshu on the Department of Telecommunications’ Sanchar Saathi portal. 

If you have already lost money, call the cybercrime helpline at 1930 or report the incident through the National Cyber Crime Reporting Portal. 

For Businesses: Block Unwanted Callers Across Your Team

A personal phone’s block list applies to that device. Businesses that need to manage unwanted callers across a team can use a central call-blocking feature. Learn more about the CallerDesk blacklist feature for business calls.

Frequently Asked Questions

What Is a Blacklist Number?

It’s a number you’ve added to your phone’s blocked list to restrict calls or messages from it.

Does the Caller Know They’ve Been Blocked?

Your phone usually doesn’t send the caller a direct notification. What happens when they call can vary by phone and network.

Can a Blacklisted Number Still Send WhatsApp Messages?

Yes. Blocking a number in your Phone app doesn’t automatically block it in WhatsApp. Block the person separately in the WhatsApp app.

How Many Numbers Can I Block?

The limit depends on your phone and app. Check your blocked list to see the options available on your device.

Will Blocking a Number Also Block SMS?

Not always. Call blocking and message blocking may use separate settings, especially on Android. If texts continue, block the number in your Messages app too.

What Should I Do If the Number Keeps Calling?

Check that you blocked the correct number. If calls come from different numbers, block each one or use your phone’s spam-filtering options. For suspected fraud, report the communication through Chakshu. If you have lost money, call 1930.

Government Sources

• TRAI: Telecom Commercial Communications Customer Preference (Second Amendment) Regulations, 2025
• Department of Telecommunications: Sanchar Saathi
• National Portal of India: Helplines