How to Block Your Phone Number When Calling Someone
Most phones make it surprisingly easy to hide your number from the person you're calling. Whether you want to protect your privacy, make a sensitive call, or simply avoid having your number saved by someone you don't know well, caller ID blocking is a built-in feature available on virtually every modern smartphone and carrier plan.
Here's how it works, what affects it, and where it gets complicated. 📞
What Does "Blocking Your Number" Actually Mean?
When you place a call, your phone sends your number as part of the call signaling data — this is what populates the recipient's caller ID display. Blocking your number tells the network to suppress that information before it reaches the other end.
The receiving phone will typically see "No Caller ID," "Private Number," "Unknown," or "Blocked" instead of your actual number. The exact label depends on the recipient's carrier and device settings.
This works at the network level, meaning your number is hidden during the call routing process — not just visually masked on your end.
How to Block Your Number Per Call
The quickest method works on almost any phone without changing any settings permanently.
*Dial 67 before the number you're calling:
*67 + 1 + area code + number For example: *67 + 1-555-867-5309
This suppresses your caller ID for that one call only. Your number shows normally on every other call. This method works on iOS, Android, and most landlines in the United States and Canada. Other countries use different codes — the UK uses 141, Australia uses 1831, and so on.
How to Block Your Number by Default (All Calls)
If you want your number hidden on every outgoing call, both major mobile operating systems offer a setting for this.
On iPhone
Go to: Settings → Phone → Show My Caller ID → toggle it off.
On Android
The path varies slightly by manufacturer, but generally:
Phone app → Settings (three-dot menu or gear icon) → Calls → Additional Settings → Caller ID → Hide Number
Some Android skins (Samsung One UI, for example) label this slightly differently, but the option is available under call settings on most devices.
Through Your Carrier
Many carriers also let you request permanent outgoing caller ID suppression on your account. This is handled at the network level rather than the device level — useful if you switch between phones frequently or want it applied regardless of device settings.
The Variables That Affect Whether It Works
Caller ID blocking is reliable in most cases, but several factors determine the actual outcome. 🔍
| Variable | What It Affects |
|---|---|
| Recipient's carrier | Some carriers display "Unknown" vs. "Private" vs. nothing at all |
| VoIP vs. cellular | VoIP-to-cellular calls can behave differently depending on the service |
| Country or region | Suppression codes vary; cross-border calls may not honor the flag |
| Business phone systems | PBX and corporate lines sometimes strip suppression flags |
| Emergency services | 911 and similar services always receive your number regardless |
One important nuance: some people have call blocking apps or carrier features that automatically reject calls with no caller ID. If you block your number and the recipient has this enabled, your call may go straight to voicemail or be rejected entirely without ringing.
What Blocking Your Number Doesn't Do
There's a common misconception that hiding your caller ID makes you completely anonymous. It doesn't — at least not technically.
- Your carrier always knows your number. The suppression only affects what's shown to the recipient.
- Law enforcement can subpoena call records regardless of whether your number was displayed.
- Some third-party caller ID services (like Hiya or Truecaller) can sometimes identify numbers even when suppressed, depending on their database methods.
- Call tracking services used by businesses may or may not log suppressed numbers, depending on their setup.
Blocking your number is a privacy measure, not an anonymity guarantee.
When *67 Doesn't Work
There are specific situations where the per-call suppression code won't achieve what you expect:
- Toll-free numbers (800, 888, 877, etc.) — These numbers have Automatic Number Identification (ANI), a separate system from caller ID that often delivers your number regardless of suppression.
- Some app-based calls (WhatsApp, FaceTime, etc.) — These use internet-based call routing. Blocking your number in your phone's settings doesn't carry over; the app itself determines what information is shared.
- Calls to your own carrier's service lines — Carriers may bypass suppression for internal routing purposes.
The Difference Between One-Time and Permanent Suppression
Both approaches are legitimate, but they serve different users.
*One-time suppression (67) works well if you occasionally need privacy on specific calls — contacting someone you don't know, calling a business you'd rather not be on a mailing list for, or handling a sensitive personal situation.
Permanent suppression (via device or carrier settings) suits people who consistently want to control how their number appears — certain professionals, people managing personal safety concerns, or anyone who simply prefers not to broadcast their number by default.
The tradeoff with permanent suppression is practical: some people and businesses won't answer calls with no caller ID, and certain services require a visible number to function correctly.
User Setup Makes All the Difference
Whether caller ID blocking works the way you need it to comes down to more than just knowing the method — it depends on who you're calling, what platform you're using, and what your ongoing privacy needs actually are. Someone making occasional personal calls has a very different situation than someone managing calls across multiple devices or using VoIP for work. The mechanics are consistent, but the right approach for any given person depends entirely on their own setup.