‘No Caller ID’ vs. ‘Unknown Caller’: What do these terms mean and what’s the difference?

💡 Need to know

• No Caller ID means it’s hidden. The person blocked their number before calling.
• Unknown Caller means it’s unavailable. Your carrier couldn’t read the number.
• Both can be harmless—or spam. Telemarketers and scammers often use these labels.
• You can’t see the number later. If it’s hidden, there’s no way to reveal it from your phone.

It’s simple. When your cell phone rings, you want to know who’s calling. But sometimes the name and number of the person trying to reach you doesn’t appear on your phone screen during incoming calls. Instead, you see a “No Caller ID” or “Unknown Caller” message. 

But what do these terms mean? And what’s the difference between the two types of unwanted calls? Are they suspicious or merely calls from people you don’t know? Don’t worry. We’re here to help. 

At Asurion, we show you how to protect your personal data while using your favorite tech, including how to stop “scam likely” calls and how to stop spam text messages. Here’s everything you need to know about No Caller ID and Unknown phone calls. 

What’s No Caller ID?

When your phone shows “No Caller ID,” it means the person calling chose to hide their number before dialing you. They turned off their caller ID on purpose, so your phone can’t display who’s calling. Some people do this for privacy, but it’s also common with telemarketers or spam calls. If you don’t recognize the call and aren’t expecting it, it’s usually safest to let it go to voicemail.

Who uses No Caller ID?

A No Caller ID call can be legit—it may be from an organization or person who simply wants to keep their contact information private. Or, a No Caller ID call can be a telemarketer or spam call. Here are a few scenarios: 

Individuals

A person may want to use No Caller ID to avoid sharing their mobile phone number. Think celebrities looking for privacy or someone calling in an anonymous complaint. Or, people with bad intentions—like scammers or stalkers—may set up No Caller ID to conceal their identity. 

Organizations 

Telemarketing companies or fundraising organizations—both legitimate and malicious—often set up No Caller ID so people won’t know who’s calling and won’t have a direct call-back number. It’s not the best customer service policy, but a company or government agency may also use No Caller ID to prevent a high volume of return phone calls. 

How does No Caller ID work? 

You can hide your phone number for one call—or, in some cases, for all outgoing calls. But keep in mind, this option may or may not appear based on your carrier. Here’s how it works:

Hide your number for one call

In the U.S. and Canada, dial *67, then enter the area code and phone number. Your number won’t appear on the recipient’s screen for that call.

To turn on No Caller ID for all calls

On iPhone®: Go to Settings > scroll down to Apps > tap Phone > select Show My Caller ID, then switch the toggle off.

On Android™ (Android 16): Open the Phone app > tap the menu icon (three vertical dots) to open a dropdown menu > tap Settings > go to Calling accounts or Additional settings > select Caller ID, then choose Hide number.

Keep in mind, some carriers control this setting. If you don’t see the option, or it’s greyed out, you may need to contact your carrier to enable caller ID blocking.

What's Unknown Caller? 

If you see “Unknown Caller” pop up on your screen, it’s not quite the same as “No Caller ID.” “No Caller ID” usually means the person intentionally blocked their number. “Unknown Caller” means your phone didn’t receive caller information from the network at all. That can happen with international calls, certain business phone systems, VoIP services, or even temporary carrier glitches. If it keeps happening, it’s worth reaching out to your carrier to see what’s going on.

How to manage anonymous calls on your iPhone

We recommend that you don’t answer calls labeled No Caller ID or Unknown Caller in case someone is trying to scam you. But anonymous calls can still be annoying. If you have an iPhone®, you can silence unwanted calls so they won’t disturb you. iPhones only allow the silencing feature, not blocking, unless you use a third-party app.

Go to your Settings app, scroll down to tap Apps, select Phone, then tap Silence Unknown Callers and toggle it on.

Taking this step may affect numbers from doctors' offices or other appointments. But if the call is legitimate, the person on the other line can always leave a message.

How to block Unknown Caller and No Caller ID calls on your Android phone

If you want to block all anonymous calls on your Android phone, follow these simple steps, which may vary slightly depending on your device: 

1. Open your Phone app. 
2. Tap the menu icon (three vertical dots) to open a dropdown menu. 
3. Select Settings > Block numbers > Block calls from unknown numbers and turn it on. 

FAQ

If I use *67, can the police or toll-free numbers still see my identity?

Yes. Using `*67` masks your phone number from standard residential and mobile lines. However, it will not hide your identity if you dial emergency services (like 911), law enforcement agencies, or toll-free numbers (like 800 or 888 numbers), which use advanced routing systems to unmask incoming lines for billing and safety purposes.

Why did a number I have saved in my contacts ring through as "Unknown Caller"?

This usually points to a temporary carrier network glitch or an issue with VoLTE/Wi-Fi calling. If a known friend's number shows up as unknown, try turning your phone off and back on again to force it to re-register with your carrier's local cell towers, or have them check if their caller ID setting was accidentally toggled off.

Do third-party spam-blocking apps catch "No Caller ID" calls?

Yes. Popular applications like Hiya, RoboKiller, and Truecaller feature advanced database filters that can automatically intercept and drop incoming calls flagged with hidden or unreadable carrier data before your phone even vibrates.