The short answer
A call that shows No Caller ID comes from someone who hid their number. Anyone can do it: dialing *67 before a number hides it for that call, for free. Scammers use it, and so do doctors, hospitals and the police.
Finding out who called is harder. In most cases you can’t, and the services that promise to tell you cost money. The details are below.
What No Caller ID, Private and Unknown mean
| What you see | What usually happened |
|---|---|
| No Caller ID, Private, Restricted, Blocked, Anonymous | The caller hid the number, for one call with *67 or on every call through their line settings |
| Unknown, Unavailable, Out of Area | The number was lost on the way: international calls, some internet phone services, some office phone systems |
Either way, there is no number to call back. That is why scammers like hidden numbers: you can’t look them up, report them or block them one by one.
Who hides their number
Not every hidden call is a scam. These callers often hide their numbers for good reasons:
- Doctors and nurses calling patients from their own cell phones, so patients don’t get their personal number.
- Hospitals and clinics, whose phone systems are often set to hide outgoing numbers.
- Police officers and some government offices.
- Ordinary people who simply don’t want to share their number.
So before you block every hidden number, think about who might need to reach you. A parent waiting on test results is the classic case.
Blocking No Caller ID on iPhone
The iPhone has no switch for hidden numbers alone. Its setting covers every number that isn’t in your contacts and that you haven’t called, hidden ones included. On iOS 26:
- Open Settings and tap Apps, then Phone.
- Tap Screen Unknown Callers.
- Choose Silence to send unknown callers straight to voicemail, or Ask Reason for Calling to have the iPhone ask them who they are and why they are calling before it rings.
Silencing everyone you don’t know also catches the pharmacy and the new doctor’s office. Check your voicemail often if you choose it.
Blocking No Caller ID on Android
Google Phone app (Pixel and many other Android phones)
- Open the Phone app and tap the three-dot menu, then Settings.
- Tap Blocked numbers.
- Turn on Unknown.
This blocks callers who hide their number. Numbers you simply haven’t saved still ring.
Samsung Galaxy
- Open the Phone app, tap the three dots, then Settings.
- Tap Block numbers.
- Turn on Block calls from unknown numbers.
It is meant for callers who hide their number. If callers you want start missing you, turn it off again.
Blocking No Caller ID on a landline
Most phone companies offer Anonymous Call Rejection. A hidden caller hears a message that you don’t take blocked calls and that they should unblock their number and call again. Your phone never rings.
| To | Dial | On a rotary phone |
|---|---|---|
| Turn Anonymous Call Rejection on | *77 | 1177 |
| Turn it off | *87 | 1187 |
Two limits. It only stops callers who hid their number on purpose, so calls that show Unknown or Out of Area still ring. And not every line has it, so call your phone company if the code does nothing. More on protecting a home phone is in scam calls on a landline.
Finding out who called
The honest answer is that you usually can’t.
- Your phone company has the number but won’t show it to you.
- Don’t count on
*69. Call return often won’t call back a hidden number. - Unmasking apps exist. They are paid services. Read the price, the trial terms and what they do with your call history before you sign up.
- If the calls are harassing or threatening, write down the date and time of each one, keep any voicemails, and call your phone company and the police. The police can ask the phone company for the records.
If a hidden caller says they are your bank, the IRS or a relative in trouble, hang up and call back on a number you already know. A real caller won’t mind.
How PhoneShield handles hidden numbers
Blocking every hidden number turns away the doctor along with the scammer. PhoneShield doesn’t refuse hidden numbers. With no number to check against a scam list, it has the front desk answer: the caller is asked who they are and why they are calling. A real caller can say so and reach a live assistant or ring through, depending on how the family set up the line. A scammer has to make their pitch to an assistant that is listening for one.
The family sees every call, hidden or not, with what the caller said. No screening catches every scam, but hidden callers stop being a guessing game for the person you are protecting. PhoneShield is $29.99 a month for one line. See how a call is handled.
Questions people ask
What does No Caller ID mean?
The caller chose to hide their number. They either dialed *67 before your number, which hides it for that one call, or their phone line is set to hide it on every call. Your phone shows No Caller ID, Private, Restricted, Blocked or Anonymous, depending on your carrier and phone.
Is No Caller ID the same as Unknown?
Not quite. No Caller ID, Private and Restricted usually mean the caller hid the number on purpose. Unknown or Unavailable usually means the number got lost on the way, which is common with international calls and some internet phone services.
Can you block No Caller ID calls?
Yes, in most cases. On a landline, dial *77 to turn on Anonymous Call Rejection where your phone company offers it. On Android, turn on the Unknown switch in the Phone app's blocked numbers settings. On an iPhone, Screen Unknown Callers in Settings, Apps, Phone sends every number you don't know, hidden ones included, to voicemail or asks them why they are calling.
How do I find out who called me with No Caller ID?
Usually you can't. The phone company knows the number but won't show it to you. Calling back with *69 does not reliably work on a hidden number. Paid unmasking services exist. If the calls are threatening or won't stop, keep a log, call your phone company and report it to the police, who can ask the phone company for the records.
Will blocking hidden numbers stop calls from my doctor?
It can. Doctors calling from their own cell phones, hospitals, police and some government offices hide their numbers. With Anonymous Call Rejection on, they hear a message asking them to unhide their number and call again. Many will, but not all.
How do I hide my own number?
Dial *67 before the number you are calling. It works for that one call and is free in the US and Canada. Your phone settings can also hide it on every call.