What is the Difference Between an Unknown Caller and No Caller ID? 

When your cell phone rings and it’s an unfamiliar number, do you pick up the call? According to the Pew Research Center, 80% of Americans don’t answer the phone if the number is unknown to them. 

There are plenty of reasons for this, including the fact that Americans receive 33 million robocalls a day, not to mention scam and spam calls, wrong number calls, and polling calls from real people. 

Often, if you don’t have a specific number saved in your phone’s address book, your phone will simply display a phone number when you receive a call. However, you might alternatively see a label like “No Caller ID” or “Unknown Caller.”

It would be easy to assume these two labels mean the same thing, but there is actually a difference. There are several reasons why a call may register as an Unknown Caller, but seeing “No Caller ID” means that the caller is actively trying to block your number. 

Before we explain the differences between these two labels on your phone, let’s take a look at where Caller ID came from and how we got to where we are! 

The controversial history of Caller ID 

Caller ID changed the game when it was introduced in 1987. By the early 1990s, as Caller ID began to gain mainstream popularity, there were debates about whether or not it was a violation of the caller’s privacy. 

Check out this excerpt from a 1990 New York Times article about the pros and cons of Caller ID: 

”We perceive it as the best technology available for thwarting obscene and threatening and harassing phone calls,” said Peter J. Ventimiglia, director of media relations for New Jersey Bell, a Bell Atlantic company.

Mr. Ventimiglia said Caller ID customers could choose not to answer the phone if they received a call from an unfamiliar or undesirable number. They can also report the numbers of intrusive or threatening callers to the police. The device even keeps track of who calls when nobody is home.

”We see Caller ID as an enhancement to privacy,” Mr. Ventimiglia said. ”It enhances the privacy of the called party. We’ve used the analogy of the peephole in the front door. We believe you have the right to know who’s calling you before you pick up the phone.”

Civil libertarians do not see it that way. ”This is a case of a company that has a great deal of personal information making money exploiting the sale of that information without the consent of the phone subscriber,” said Marc Rotenberg, director of the Washington Office of Computer Professionals for Social Responsibility, a national organization based in Palo Alto, Calif.

To use Caller ID in the 90s, you would purchase Caller ID hardware that plugged into your phone and told you the phone number of the person calling. If a number you recognized came across the display, you would know who was calling. 

Later, the Caller ID displayed the name associated with the phone number. However, this was for landlines. Even though Caller ID eventually became a standard option with most landlines, without the need for additional hardware, cell phones have typically not displayed names unless those names are programmed into your address book. 

Do cell phones have Caller ID? 

Cell phones have what is very similar to earlier forms of Caller ID: They display the number that is calling you. 

However, unlike landline Caller ID services, most cell phones don’t automatically display the name associated with an incoming phone number unless you’ve saved that contact in your phone. This is why you’ll often see just the phone number displayed when receiving calls from unfamiliar numbers.

Some cell phone carriers offer enhanced Caller ID services as an add-on feature. These services can provide the name associated with incoming calls, similar to how landline Caller ID worked, even for numbers not saved in your contacts. However, this usually comes with an additional monthly fee.

App developers have created Caller ID apps for both Android phones and iPhones, including: 

• TrueCaller
• Hiya
• CallApp
• Whoscall

Modern smartphones have also evolved beyond basic Caller ID to include additional features like:

• Spam call identification
• Business name display for verified business numbers
• Location information (like the city and state associated with the number)
• Integration with third-party apps that can provide additional caller information
• The ability to automatically screen and filter suspected spam calls

Despite these advances, cell phone Caller ID still faces limitations. For instance, the rise of spoofed numbers and robocalls has made it increasingly difficult to trust the number that appears on your screen. This is one reason why many people now rely more heavily on their contact list and tend to ignore calls from unknown numbers.

What it means when you see “Unknown Caller” on your phone display

When your phone displays “Unknown Caller,” it typically means that your cell phone carrier has received a call for you but couldn’t verify or receive complete information about the number calling you. 

This can happen for several reasons:

1. The call is from an area or carrier that doesn’t share caller information with your network
2. The call has been routed through older telecommunications equipment that doesn’t support modern caller ID features
3. The call is from certain types of business phone systems or PBX (Private Branch Exchange) systems
4. The call originates from outside the country, where caller information sharing may be limited
5. The caller is using a service or method that doesn’t transmit complete caller information

Unlike “No Caller ID,” which indicates an intentional blocking of information by the caller, “Unknown Caller” usually means the caller’s information simply isn’t available to your phone’s network. 

Should you be suspicious of “Unknown Caller” calls? 

You do not need to assume that a “Unknown Caller” call is a scammer or someone who is intentionally hiding their identity from you. However, it is always a good idea to be skeptical of calls from anyone you don’t have programmed into your phone as one of your contacts. 

It is still wise to exercise caution! The caller may be completely legitimate, such as a government agency, business, or organization, but you should also take steps to avoid falling for scams. 

If you receive a call from a legitimate caller with an unknown number, they will typically: 

• Identify themselves clearly, without trying to frighten or overwhelm you with information
• Leave a voicemail identifying themselves if you don’t answer
• Provide a callback number

They may also send a follow-up email or text if they have your contact information for legitimate business purposes 

What it means when your phone says “No Caller ID”

“No Caller ID” should set off some alarm bells. This label indicates that the person who is calling you has deliberately blocked their number so that it can’t be displayed. This means that they have taken steps to hide their identity. 

They may have:

• Dialed *67 before making the call
• Had their number permanently blocked through their phone carrier
• Used a phone service that blocks their caller ID information
• Installed a caller ID-blocking app like Hushed or Sideline

There are some legitimate reasons why someone might want to block their number from showing up on caller ID. For example: 

• Medical professionals calling patients from personal phones
• Law enforcement officials protecting their private numbers
• Domestic violence survivors who need to keep their number private
• Business people who need to make calls from personal phones but don’t want to share their private numbers

However, “No Caller ID” calls are also commonly associated with unwanted or potentially malicious calls because:

• Scammers often block their numbers to avoid being traced or reported
• Telemarketers might block their numbers to increase the likelihood of someone answering
• Harassers may hide their numbers to avoid consequences
• Robocallers frequently mask their real numbers

What should you do when you get a “No Caller ID” call? 

Here are some recommended steps to take if you receive a “No Caller ID” call: 

1. Learn how scammers operate so you can recognize red flags
2. Let the call go to voicemail if you’re not expecting an important call from someone who might block their number
3. If you do answer, never provide personal or financial information to the caller
4. If it’s a legitimate caller, they should identify themselves immediately and explain why their number is blocked
5. For business-related calls, ask for a callback number or email address to verify their identity
6. Consider enabling your phone’s setting to automatically decline calls from blocked numbers if they become a nuisance

Check out WhatIsMyIPAddress.com’s Reverse Phone Lookup Tool

WhatIsMyIPAddress.com offers a useful Reverse Phone Lookup Tool that you can use to look up unfamiliar numbers. When a number you don’t recognize comes across your phone, search for it using our tool to find out who called you!