How to Block Your Phone Number While Making a Call

Whether you're returning a call to an unknown number, contacting a business you'd rather not have call you back, or simply protecting your privacy, blocking your number while calling is a built-in feature on virtually every modern smartphone and carrier plan. Here's how it works, what your options are, and why the right method depends heavily on your situation.

What It Means to "Block" Your Number on Outgoing Calls

When you block your number on an outgoing call, you're instructing the phone network to send your call as "No Caller ID," "Private Number," or "Unknown" — meaning the recipient's phone won't display your number. This is done through a mechanism called CLIR (Calling Line Identification Restriction), which is part of how voice calls are routed across cellular and landline networks.

It's worth being clear about what this does and doesn't do: the recipient's phone won't show your number, but it doesn't make you completely anonymous. Carriers retain call records, and in legal contexts your number can still be traced. Emergency services (911 / 999) can also see your number regardless of any restriction you apply.

Method 1: The *67 Prefix (Per-Call Blocking)

The most universally known method works on nearly all US and Canadian carriers, as well as many international networks.

How to use it:

• Before dialing the number, type *67 followed immediately by the full number, including area code.
• Example: *67 555-867-5309
• Press call as normal.

The call goes through as it normally would — you just appear as "No Caller ID" or "Private" on the recipient's end.

Key things to know:

• This only applies to that single call. Your number displays normally on your next call.
• It works on both Android and iPhone, regardless of carrier, in North America.
• On some international networks the equivalent code differs — for example, #31# is used in many European countries before the number.
• It also works on landlines.

Method 2: Carrier-Level Permanent Blocking

If you want every call you make to go out as private by default, most major carriers offer a line-wide caller ID block you can request or enable yourself.

Options vary by carrier but typically include:

• Calling your carrier's customer service line and requesting permanent CLIR
• Logging into your account portal and toggling "Block Caller ID"
• Dialing a carrier-specific code (commonly *31 or #31# depending on region)

📋 Tradeoff to understand: Once permanent blocking is on, you'd need to un-block your number for individual calls — typically by dialing *82 before the number in North America. Some businesses, toll-free numbers, and government lines automatically reject calls from blocked numbers, so blanket blocking can create friction.

Method 3: iPhone Settings (Per-Line or Per-Call)

On iPhone, Apple provides a built-in toggle through the carrier settings:

• Go to Settings → Phone → Show My Caller ID
• Toggle it off to hide your number on all outgoing calls

This functions identically to requesting permanent blocking through your carrier — it sends a CLIR instruction with every call. The same caveat applies: some numbers won't accept blocked calls.

For a per-call approach on iPhone, *67 still works even when typed into the native Phone app before the number.

Method 4: Android Settings (Varies by Manufacturer and Carrier)

Android doesn't have a single universal path, because the interface depends on the device manufacturer, Android version, and carrier.

Common paths include:

• Stock Android / Pixel: Phone app → More (⋮) → Settings → Calls → Additional Settings → Caller ID → Hide Number
• Samsung (One UI): Phone app → More Options → Settings → Supplementary Services → Show Caller ID → Hide Number
• Carrier-modified builds: The option may be hidden, greyed out, or require a carrier unlock

On some Android builds — particularly those with heavy carrier customization — the toggle may not appear at all, and *67 becomes the more reliable per-call fallback.

Comparing Your Main Options 📞

What Affects Whether This Works Reliably

A few variables determine how well number blocking functions in practice:

• Your carrier's support: Some prepaid or MVNO carriers don't fully support CLIR or handle the *67 code inconsistently.
• VoIP and app-based calls: Calls made through apps like WhatsApp, FaceTime Audio, or Google Voice operate on different infrastructure. *67 doesn't apply — each app has its own privacy or number-masking settings.
• The recipient's setup: Calls to toll-free numbers (800, 888, etc.) often automatically reject private numbers. The same is true for many businesses using call-screening software.
• International calling: CLIR codes vary by country and aren't globally standardized. Calling internationally with a blocked number may behave differently depending on both the originating and destination country's network rules.
• Android version and ROM: On heavily customized Android builds, native settings may not expose the caller ID toggle at all.

When Blocking Doesn't Apply the Same Way

If you're using a second number app (like Google Voice, Hushed, or similar services), the number the recipient sees is already the app's assigned number — not your real mobile number. In that case, blocking caller ID at the phone level may not be necessary depending on your goal.

Similarly, if you're calling from a work phone or a number provided by an employer, caller ID behavior may be managed at the PBX or business phone system level, outside your individual control.

The right approach shifts depending on whether you're on a personal device, a business line, a VoIP service, or a mobile carrier — and whether you need one-time privacy or a persistent setting across all your calls.