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Most of us have gotten those calls: "Your car's warranty is about to expire...", whether we have a car or not. Aside from going to DoNotCall.gov or calling 1-888-382-1222 to be added to a do-not-call list, you can also block specific phone numbers from your phone. 

But what if you need to block someone you know, like a coworker, a neighbor, or an old flame? Can they tell you've blocked them? We'll walk you through the ways someone may be able to tell if their number was blocked.

Can someone tell if I block their number?

First things first, if you block someone's number, they won't find out right away, if at all. They won't get a notification saying they were blocked and won't be able to see it plainly anywhere, but they can infer it. There are ways a person can figure out if they were likely blocked, like sending you texts and calling you. 

1. Sending you a text

If you and the other person you blocked both use iPhones, your text message exchange is through iMessage, so they show up in blue.

This text is delivered as an iMessage so it comes up in blue and says Delivered, which means your number isn't blocked

Image: Maria Diaz / ZDNet

If they weren't blocked and decided to send you a text message, it'd come up asDelivered.

The signs are in the colors

After blocking my number on the other phone, the message was delivered as a text instead of an iMessage

Image: Maria Diaz / ZDNet

If the sent text message looks green instead, it means it was sent as an SMS instead of iMessage. They may also seeNot Deliveredin red under the green text bubble or the message may go through as an iMessage and just not show if it wasDelivered. These can all be clues that they may have been blocked by the other person.

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However, iMessages can show up in green or not show asDeliveredwhen someone's phone is off or if they don't have a signal or internet connection at the time. So the other party may assume that's the case before realizing they were blocked. 

2. If the blocked number calls yours

When someone thinks they're blocked, it's all about putting the pieces together to determine if the other person has in fact blocked their number. If you call someone that hasn't blocked your number, you typically hear several rings before it goes to voicemail.

When you call a number that has blocked yours, you may hear one or half a ring or no rings at all and then the call will go to voicemail. If it goes straight to voicemail, their phone may also be off or out of range, or they may have temporarily turned on Do Not Disturb mode to work, drive, or sleep.

If the person you blocked calls your number, they'll go to voicemail and can leave a message, but you won't get a missed call or voicemail notification.

If the "Someone" you blocked calls your number, they'll probably go straight to voicemail

Image: Maria Diaz / ZDNet

3. They may hide their number

If the blocked party's messages are delivered as text when they used to be iMessages and their calls go straight to voicemail consistently, they may try calling you from a different number or hiding their number. They can hide their number by dialing *67 before your phone number and the call will come in as No Caller ID.

If the blocked caller gets through from a different number or by hiding their number, then they'll probably be pretty certain you have blocked them.

Dialing *67 + phone number. So, *67(XXX)-XXX-XXXX, shows up as No Caller ID on the other phone

Image: Maria Diaz / ZDNet

For my peace of mind, I wouldn't answer No Caller ID calls after blocking someone, unless I was expecting a very important call.

Also: How to find and remove spyware from your phone

If you're the one that was blocked, keep in mind that though no one wants to find themselves being blocked by another person, especially if it's someone you care about, the best thing to do is to allow that person the privacy and time to process their needs for doing so. 

Incoming call with no caller ID a hidden phone number using *67

Image: Maria Diaz / ZDNet

FAQs

Can someone tell if I block their number on Android?

Android is not as straightforward as iPhone when trying to figure out if someone blocked you. Since there is no iMessage in Android, it's a little trickier to determine. Some phones offer read and delivered receipts, so if that's the case for yours and the blocked person's phone and they're not seeing the receipts, they may try doing some digging. 

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Either way, if their calls to your number don't go through and they hide their number to call you and do get through, they will likely figure out you blocked their number regardless of delivered or read receipts.

Does blocking a phone number block it on Whatsapp?

When you block someone's number, you won't receive their calls, texts or notifications for voicemail. But if you also use Whatsapp to communicate, their number won't also be blocked on the messaging app automatically. 

Whatsapp is a messaging app independent of your phone manufacturer and provider. To block someone from contacting you via Whatsapp, you'll have to do it within the app. Going to the contact info in Whatsapp and tapping on Block (this person) will do the trick.

How do I know if someone blocked me on Whatsapp?

If you think someone has blocked you on Whatsapp, you can send them a message to check. When someone receives a Whatsapp message, two checks will show up when it's been delivered and they'll turn blue when it's been read. If only one gray checkmark comes up, then the message hasn't been delivered to the recipient.

It may not be delivered if that person doesn't have internet service at the time, or if their phone is off. If you have other reasons to think they might have blocked you on Whatsapp, give it a couple of days and if the checkmark never doubles, they probably have.

Can someone tell if I block their number on a landline?

If you're getting unwanted calls on your landline, you may wonder if someone can tell if you've blocked their number, whether you did it with a call blocker or through your phone carrier. The blocked party won't get a notification that they've been blocked, but if they call your landline they may hear a busy signal, or a message that their call couldn't go through or that the number is busy. Which variation of this they hear will depend on the carrier. 

The blocked caller can't leave a voicemail on a landline like they'd be able to when blocked on your iPhone, for example. Their call simply won't go through.

See also

How to better organize text messages on your iPhone, thanks to iOS 17How to transfer data from Android to an iPhone: 2 simple and fast waysHow to turn on 80% charging limit on the iPhone 15 to save battery healthHow to leave a FaceTime voice or video message when your call goes unanswered

• How to better organize text messages on your iPhone, thanks to iOS 17
• How to transfer data from Android to an iPhone: 2 simple and fast ways
• How to turn on 80% charging limit on the iPhone 15 to save battery health
• How to leave a FaceTime voice or video message when your call goes unanswered