How to Block Call Display: Methods, Settings, and What Actually Works

Blocking your call display — also known as caller ID blocking or number suppression — means the person you're calling sees "Private Number," "Unknown," or "No Caller ID" instead of your phone number. It's a legitimate feature built into phone networks and devices, used for everything from professional privacy to personal safety.

Here's how it actually works, what your options are, and why results can vary depending on your setup.

What "Blocking Call Display" Actually Does

When you make a phone call, your number is transmitted as part of the signalling data sent across the network — specifically through a field called CLI (Calling Line Identification). Blocking call display instructs the network to suppress this information before it reaches the recipient's phone.

This is different from spoofing (replacing your number with a fake one). Blocking simply withholds it. Most carriers and telecom regulators permit this for legitimate personal use.

It's worth noting: call display blocking affects what the recipient sees, not what the carrier logs. Your number is still recorded on the carrier's end and can be accessed by emergency services and law enforcement regardless of suppression settings.

Method 1: Per-Call Blocking with a Star Code 📞

The most universal method requires no settings changes at all.

Before dialing, prefix the number with:

• *67 (Canada, United States)
• 141 (United Kingdom)
• #31# (many European countries and Australia)

Example: Dialing *67 555-867-5309 in North America will suppress your number for that call only.

This works on most landlines, mobile phones, and even VoIP services. It's temporary — your number displays normally on all other calls.

If you're outside these regions, your carrier's support documentation will list the correct code.

Method 2: Permanent Suppression Through Phone Settings

If you want your number hidden on every outgoing call by default, both Android and iOS offer a native toggle.

On iPhone (iOS): Settings → Phone → Show My Caller ID → Toggle off

On Android: The path varies by manufacturer, but generally: Phone app → Menu/Settings → Calls → Additional Settings → Caller ID → Hide Number

Some Android versions label this differently depending on the manufacturer skin (Samsung One UI, stock Android, etc.). If you can't find it, searching "caller ID" in your device's Settings search bar usually surfaces it.

On a landline or desk phone: You'll typically need to contact your carrier directly to enable permanent line blocking on the account. This is a network-level setting, not a device setting.

Method 3: Through Your Carrier Account 🔒

Many carriers allow number suppression to be configured directly on your account — separate from anything you do on the device itself. This is particularly relevant for:

• Business lines where multiple extensions need consistent suppression
• Landlines that don't have built-in caller ID menus
• VoIP services like Google Voice, Vonage, or business telephony platforms

Log into your carrier's account portal or call customer support and ask about outbound caller ID suppression or CLI restriction. Some carriers offer this at no charge; others may apply a small monthly fee depending on the plan.

Method 4: VoIP and App-Based Calling

If you're using a VoIP app or second-line service (such as Google Voice, Skype, TextNow, or a business softphone), the caller ID settings live within the app, not your phone's native settings.

Most VoIP platforms have a dedicated caller ID section in the account or app settings. Some allow you to set a different outbound number entirely (within regulatory limits), while others let you toggle suppression on or off per call.

One variable worth understanding here: VoIP calls route through internet infrastructure, and how CLI suppression is handled depends on both the app and the receiving carrier. Not every suppression setting propagates identically across all carrier networks globally.

Variables That Change the Outcome

Blocking call display isn't one-size-fits-all. Several factors shape whether it works cleanly in your situation:

• Device and OS version — Older Android versions may bury or omit the caller ID toggle entirely
• Carrier support — Not all carriers honour *67 on all plan types, particularly budget or MVNO plans
• VoIP vs. cellular — Suppression behaviour on VoIP apps depends on the platform's own implementation
• Recipient's service — Some toll-free numbers, emergency lines, and certain business switchboards are configured to reject anonymous calls or unmask suppressed numbers
• International calls — Star codes and suppression behaviour don't always carry across international call routing

When Call Display Blocking Doesn't Work

There are situations where suppression is bypassed or ineffective:

• Emergency services (911/999/112): Your number is always delivered regardless of suppression
• Some business phone systems: Corporate PBX systems can be configured to receive your real number even when suppressed
• Premium-rate and toll-free numbers: Some are set up to unmask blocked callers
• Certain call-screening apps: Apps like Hiya, Nomorobo, or carrier-native spam filters may still flag or evaluate your call even if the number is hidden

The Factors That Depend on Your Specific Setup

Whether the built-in phone toggle, a star code, or a carrier-level setting is the right approach comes down to a handful of things only you know: which device you're using, which carrier you're on, whether you need suppression on every call or just occasionally, and whether you're calling domestically or internationally.

Most people find the per-call star code sufficient for occasional use. Permanent suppression through device settings or the carrier account makes more sense if privacy is a consistent priority. VoIP users are working within a different set of controls entirely.

The method that fits depends on where your calls actually originate — and how consistently you need the suppression to apply. 📋