How to Block Your Number When You Call Out
Most phones let you hide your caller ID before placing a call — so the person you're calling sees "No Caller ID," "Private Number," or "Unknown" instead of your number. It's a standard feature built into virtually every mobile and landline system, and it works in a few different ways depending on your device, carrier, and how often you want the block applied.
Here's how it actually works, and what affects whether it works the way you expect.
Why Caller ID Blocking Exists
When you make a call, your network transmits your number as part of the call setup process. Caller ID is simply the display of that number on the recipient's end. Blocking it tells the network to suppress that information before the call is delivered — your number is still used to route the call, but it's flagged as private so it doesn't appear on the other person's screen.
This is different from spoofing (which replaces your number with a fake one). Blocking simply withholds it.
Method 1: Dial a Prefix Before the Number
The most universal method — works on virtually any phone, any carrier, any country with a standard phone network.
In the US and Canada, dial *67 before the number:
*67 + [area code] + [number] Example: *67 555 867 5309
The call goes through normally. The recipient sees a blocked or private number. This applies per call only — your next call goes out with your number visible again.
In the UK, the equivalent prefix is 141. In Australia, it's 1831. Most countries have a similar code — it's worth confirming with your carrier if you're outside North America.
Method 2: Turn Off Caller ID Globally in Your Phone Settings 📱
If you want every outgoing call to go out with your number hidden by default, both iOS and Android let you set this at the device level.
On iPhone:
- Go to Settings → Phone → Show My Caller ID
- Toggle it off
On Android (stock/Google):
- Open the Phone app → Settings (three-dot menu) → Calls → Additional Settings → Caller ID
- Select Hide number
The exact path varies by Android manufacturer. Samsung, OnePlus, and others may nest this option differently — look under Call Settings or Supplementary Services if you can't find it immediately.
One important caveat: This setting is carrier-dependent. Some carriers override it, meaning your number may still appear even with the toggle off. If you turn off caller ID in settings and it doesn't seem to work, the per-call prefix method (*67) is more reliable.
Method 3: Contact Your Carrier
Carriers can apply a permanent line block at the network level — your number is suppressed by default on every call without you needing to do anything on the device. This is sometimes called a CLIR (Calling Line Identification Restriction) setting.
This option is more common with postpaid plans and business accounts. Some carriers offer it for free; others charge a small monthly fee or require a call to customer service to enable it.
If you go this route, you can usually unblock on a per-call basis by dialing *82 before the number — the reverse of *67.
What Affects Whether Blocking Actually Works
Blocking your number doesn't guarantee the recipient sees nothing useful. Several variables change the outcome:
| Factor | What It Means |
|---|---|
| Recipient's carrier | Some carriers display "No Caller ID" clearly; others may show "Unknown" or nothing |
| VoIP and app-based calls | Apps like WhatsApp, FaceTime, or Zoom use internet-based calling — standard *67 blocking doesn't apply the same way |
| Emergency services | 911 (and equivalent services) always receive your real number regardless of blocking |
| Spam/robocall filters | Many smartphones now auto-label blocked numbers as potential spam |
| Business phone systems | Some PBX systems strip or log caller data differently |
| Toll-free numbers | Businesses with toll-free lines can often still see your number through ANI (Automatic Number Identification), which bypasses standard caller ID blocking |
That last point is worth emphasizing: caller ID blocking and ANI are different systems. Caller ID is a display feature. ANI is a billing/routing mechanism that carriers use, and it's not suppressed by *67 or device settings. When you call an 800 number, the business may still receive your number through ANI even if you've blocked caller ID.
Per-Call vs. Always-On: Different Use Cases 🔒
How you should set this up depends heavily on how often you need the block and what you're trying to achieve.
- Occasional blocking — the
*67prefix is the simplest approach. No settings to change, no risk of accidentally blocking calls you didn't mean to. - Always-on blocking with occasional unblocking — a carrier-level block combined with
*82for exceptions gives you the cleanest experience. - Device-level toggle — convenient, but only reliable if your carrier supports and respects the setting.
People who regularly call clients, sources, or contacts they'd prefer not to have their personal number also tend to consider using a second number through a VoIP app — which raises a different set of considerations around call quality, app permissions, and how those services handle identity.
The Part That Depends on Your Situation
Whether any of these methods does exactly what you need comes down to specifics that vary widely: which carrier you're on, whether you're calling landlines or mobiles, whether toll-free numbers are in the mix, and how the recipient's phone or system handles blocked calls. The technical side is straightforward — the right approach for your setup is a different question.