How to Block Caller ID: Methods, Options, and What Affects Your Results

Blocking your caller ID means your phone number appears as "Unknown," "Private," or "No Caller ID" on the recipient's screen instead of your actual number. It's a legitimate privacy tool used by professionals, researchers, domestic abuse survivors, and anyone who simply doesn't want to broadcast their number on every call. The mechanics are straightforward, but the right method depends on factors that vary considerably from one person to the next.

How Caller ID Blocking Actually Works

When you make a phone call, your network transmits your number as part of the call setup process using a signal standard called CLI (Calling Line Identification). Blocking your caller ID instructs the network to suppress that data before it reaches the recipient's carrier. The suppression happens at the network level — the receiving end simply gets no number to display.

This is different from spoofing, which replaces your real number with a fake one. Blocking removes the number entirely. It's legal, built into carrier infrastructure, and doesn't require any special hardware.

Method 1: Per-Call Blocking With a Prefix Code

The simplest method works on virtually every landline and most mobile phones in the US and Canada: dial *67 before the number you're calling.

• Format: *67 + [area code] + [number]
• Works on a call-by-call basis only
• Free, requires no setup
• The recipient sees "Private Number," "Blocked," or "No Caller ID"

In the UK, the equivalent prefix is 141. Other countries use different codes — check with your local carrier if you're outside North America.

The limitation: This only blocks one call at a time. If you frequently need privacy, dialing a prefix every time becomes tedious.

Method 2: Permanent Caller ID Blocking Through Your Carrier

Most carriers allow you to request permanent outgoing number suppression on your account. This means every call you make goes out as private by default.

• Available through your carrier's customer service or account settings
• Often listed as "Caller ID Restriction" or "Line Blocking"
• Some carriers charge a small monthly fee; others include it for free
• Works across all calls from that line without any prefix

If you have permanent blocking enabled but want to reveal your number for a specific call, dial *82 before the number. This temporarily unblocks your ID for that one call.

Method 3: Blocking Caller ID on iPhone

On iOS, go to Settings → Phone → Show My Caller ID and toggle it off. This applies to all outgoing calls from that device.

⚠️ One important caveat: this setting works with your carrier's cooperation. Some carriers — particularly MVNOs or prepaid providers — don't fully honor this toggle, meaning your number may still show up. If you're unsure whether it's working, have someone check what appears on their end when you call.

Method 4: Blocking Caller ID on Android

Android doesn't have a single universal path because manufacturers and carriers customize the interface. Common routes include:

• Phone app → Settings → Calls → Additional Settings → Caller ID → Hide Number
• Phone app → More options (three dots) → Settings → Supplementary Services → Show Caller ID

On some carrier-locked Android phones, this option may be hidden or grayed out entirely. In those cases, the *67 prefix or a carrier-level account change is your fallback.

Method 5: Third-Party Calling Apps

Apps like Google Voice, Hushed, Burner, and similar second-number services give you a separate number to call from, effectively keeping your real number private without blocking anything. The recipient sees the app's assigned number, not yours.

This approach is meaningfully different from traditional caller ID blocking:

For users who need a consistently private but reachable number — freelancers, people dating online, small business owners — the second-number approach often makes more practical sense than true blocking.

What Determines Whether Blocking Actually Works

Not every blocking method succeeds in every situation. Several variables affect the outcome:

Carrier support: Your carrier has to cooperate. If they don't support the *67 standard or the account-level restriction properly, suppression may fail silently.

Call type: VoIP calls (calls made over the internet) don't always follow traditional CLI rules. Apps like WhatsApp, FaceTime, and Messenger handle caller ID differently — often showing your registered account name or number regardless of phone-level settings.

Recipient's carrier settings: Some carriers and phone systems are configured to reject anonymous calls outright. If someone has call blocking for unknown numbers turned on, your blocked call may never ring through.

Business and emergency lines: Caller ID blocking is often overridden when calling 911 or other emergency services, and many business phone systems are configured to display your number regardless of suppression.

International calls: Cross-border CLI suppression is inconsistent. A *67 block that works perfectly domestically may not carry through to an international recipient.

The Factor That Varies Most: Your Setup and Use Case 🔒

Whether you need per-call flexibility, permanent suppression, a reachable private number, or something that works reliably across international borders changes which method actually fits. A freelancer using a personal phone for client calls has different needs than someone on a corporate line or a person using a prepaid carrier with limited feature support. The method that's invisible and effortless for one setup may simply not function on another.