How to Block Your Telephone Number When Calling Someone

Most phones make your number visible to whoever you're calling — but that doesn't have to be the case. Whether you want privacy on a one-off call or prefer to keep your number hidden by default, there are several reliable ways to block your caller ID. The method that works best depends on your device, carrier, and how often you need the feature.

What "Blocking Your Number" Actually Means

When you place a call, your phone typically sends your number to the recipient's device via a signal called Caller ID, which is transmitted as part of the call setup process. Blocking your number suppresses this transmission, replacing your number with labels like "Private Number," "Unknown," or "No Caller ID" on the recipient's screen.

This is sometimes called Caller ID blocking or outgoing number suppression. It's legal and widely supported — though it's worth knowing that emergency services (like 911) and some business lines can still identify your number regardless of suppression settings.

Method 1: Dial a Prefix Code Before the Number 📞

The simplest approach requires no settings changes at all. Before dialing, add a short code:

These prefix codes are per-call suppressions — they only hide your number for that single call. Your number appears normally on every other call. This is ideal if you only occasionally need privacy without changing any permanent settings.

Method 2: Change Your Phone's Caller ID Settings

Both Android and iOS allow you to hide your number for all outgoing calls through the phone app's settings.

On Android: Navigate to the Phone app → Settings → Calls → Additional Settings (sometimes labeled Supplementary Services or More Settings) → Caller ID → select Hide number. The exact path varies depending on your Android version and manufacturer skin (Samsung One UI, stock Android, etc.).

On iPhone: Go to Settings → Phone → Show My Caller ID → toggle it off.

Once disabled, every outgoing call will suppress your number until you re-enable the setting. Keep in mind that this setting is processed by your carrier, so some carriers may override it or require their own activation.

Method 3: Contact Your Carrier for a Permanent Block

If the in-device settings don't work — or if you want a network-level solution — your carrier can apply permanent outgoing Caller ID blocking directly on your account. This is common with both mobile and landline providers.

Some carriers offer this free; others may charge a small monthly fee or require a call to customer service. Business accounts often have more granular control over Caller ID, including the ability to display a company number rather than an individual extension.

If you've enabled per-line blocking but want to un-block for a specific call, dialing *82 (in the US/Canada) before the number temporarily reveals your Caller ID for that call only.

Method 4: Use a VoIP or Third-Party Calling App 🔒

Apps built on VoIP (Voice over Internet Protocol) technology — such as Google Voice, Skype, or various burner number apps — can place calls that display a different number entirely or no number at all. This goes beyond simple suppression and gives you more control over what the recipient sees.

This approach is common for:

• People who make frequent calls they'd prefer to keep separate from their personal number
• Remote workers using a business line through their personal device
• Anyone who wants a secondary number without a second SIM

The tradeoff is that call quality depends on your internet connection, and the feature set varies significantly between apps and subscription tiers.

Variables That Affect How This Works for You

No single method is universally best. Several factors shape which approach makes sense:

• Device type and OS version — Menu paths differ across manufacturers and software updates
• Carrier policies — Some carriers, especially MVNOs, handle Caller ID settings differently or require backend requests
• Frequency of use — Occasional blocking favors prefix codes; habitual blocking favors a system-level setting
• Call type — Standard cellular calls, Wi-Fi calling, and VoIP calls each handle Caller ID suppression differently
• Recipient setup — Some recipients use call-blocking apps that automatically reject calls from private or unknown numbers, so suppressing your number may mean the call doesn't go through at all

When Number Blocking Doesn't Work

There are situations where Caller ID blocking is overridden or ineffective:

• Emergency services always receive your real number, regardless of suppression
• Toll-free numbers and many call centers use ANI (Automatic Number Identification), a separate system from Caller ID that cannot be suppressed through standard methods
• Some VoIP providers pass through real numbers at the network level even when apps claim to hide them
• Business phone systems with advanced screening may reject or flag private numbers automatically

The Gap That Only Your Setup Can Fill

Understanding how Caller ID blocking works is the straightforward part. The part that varies is everything specific to your situation — your carrier's policies, your device's software version, whether you're on cellular or VoIP, and how often you actually need calls to go out without your number attached. Those factors together determine which method will work reliably for you and which might create friction you didn't expect.