How to Block Your Number When You Make a Call

Most phones give you at least two ways to hide your caller ID — a per-call code you type before dialing, or a setting buried in your phone app that keeps your number hidden every time. Neither approach is complicated, but which one actually works depends on your carrier, your device, and the type of call you're making.

Here's how it works, and what to watch for.

The Two Core Methods

Per-Call Blocking (The Quick Code)

The fastest method works on virtually every phone network in the US, UK, Canada, and most of Europe. Before you dial the number, prefix it with:

• *67 (North America)
• 141 (UK, on most carriers)
• #31# (many European and international networks)

So instead of dialing 555-867-5309, you'd dial *67-555-867-5309. The call goes through normally — the recipient just sees "No Caller ID," "Private Number," or "Unknown" depending on their phone and carrier. Your number is hidden for that call only.

This method doesn't require any settings change and resets after the call ends.

System-Wide Caller ID Blocking

If you want your number hidden on every outgoing call without typing a prefix each time, most smartphones let you toggle this in settings.

On iPhone: Settings → Phone → Show My Caller ID → toggle off

On Android: This varies by manufacturer. Generally: Phone app → Settings (three dots or gear icon) → Calls → Additional Settings → Caller ID → Hide number

On a carrier level: Most carriers let you request permanent line blocking — sometimes called CLIR (Calling Line Identification Restriction). You call or chat with your carrier, and they apply it to your account. Some carriers charge for this; others do it free.

What Actually Changes When You Block Your Number

When you block your caller ID, you're instructing your carrier's network to suppress the CLI (Calling Line Identification) data that normally travels with your call. The receiving carrier gets the call, but the identifying metadata is stripped or flagged as private before it reaches the recipient's phone.

This is a network-level function, not just a display trick on your phone. The call routes normally — blocking your number doesn't affect call quality, connection speed, or anything the recipient experiences other than seeing no number.

Variables That Affect Whether It Works 📵

Caller ID blocking isn't guaranteed to work in every situation. Several factors shape the outcome:

This last point catches people off guard. ANI is a different data channel from standard caller ID — it exists specifically for billing and routing purposes, and businesses that pay for it can often see your number even when you've blocked it.

VoIP and App-Based Calls Work Differently

If you're calling through an app rather than your phone's native dialer, the blocking rules shift significantly. Apps like WhatsApp, Zoom Phone, Google Voice, and Skype manage their own caller ID independently of your phone's settings.

• *67 does nothing on most VoIP calls made through apps
• System-wide caller ID settings on your phone typically don't apply to app-based calls
• These apps display their own number (often a registered VoIP number) or your Google Voice number — not your personal mobile number to begin with

If privacy on app-based calls matters to you, the approach is different: it's less about blocking and more about which number those apps are associated with.

The Spectrum of Use Cases

Someone making a single private call occasionally will find *67 perfectly adequate — no setup, no settings change, works immediately. Someone who never wants their number visible and makes calls purely through their carrier's native dialer might prefer system-wide blocking at the account level.

A freelancer using multiple lines, a business user on a VOIP system, or someone who primarily communicates through messaging apps is working with a completely different set of tools — where carrier-level caller ID blocking may be largely irrelevant.

🔒 The method that makes sense depends heavily on how often you need the number hidden, what kind of calls you're making (cellular vs. app-based), and whether the numbers you're calling are likely to use ANI — which standard blocking won't stop.

Your own call habits and the types of numbers you're dialing are what determine which approach is actually worth using.