What blocking your caller ID actually does

When you block your caller ID, the person you call sees "Unknown," "Private," or "Blocked" instead of your phone number. Your number is still transmitted to the phone company and to law enforcement if they subpoena it — blocking only hides it from the person receiving the call. It does not make you anonymous to the system itself.

Most phone carriers let you block your number on a per-call basis or set it as your default. The method depends on whether you have a landline, a mobile phone, or use internet calling. Blocking works differently on each type of service, and some carriers charge for the feature while others include it free.

Key Takeaways

  • You can block your caller ID on individual calls by dialing *67 before the number on most landlines and some mobile carriers, though this does not work on all networks.
  • Mobile phone settings let you hide your number by default through your carrier's settings app or by contacting customer service, but the process varies by carrier and phone type.
  • Internet calling services like Google Voice and Skype have built-in options to show or hide your number, and these settings are usually found in the app itself rather than through your carrier.
  • Blocking your caller ID does not prevent the phone company or law enforcement from seeing your real number — it only hides it from the person you are calling.
  • Some businesses and government offices refuse to accept calls from blocked numbers, so you may need to unblock before calling certain places.

Using *67 to block on a single call

The simplest way to block your number on a landline is to dial *67 before the phone number. You dial *67, then the area code and number. The recipient sees a blocked or private number. This works on most traditional landlines and some mobile carriers, but not all — AT&T, Verizon, and T-Mobile support it on most plans, though some prepaid or older plans may not.

On a mobile phone, *67 works less reliably. It may work on some carriers and not others, and some carriers have disabled it entirely. The only way to know is to try it: dial *67, then the number. If it does not work, you will hear a message or the call will fail. If you use this method regularly, test it once with a friend to confirm your carrier supports it.

The downside is that you have to remember to dial *67 every time. If you forget, your number shows. There is no way to set *67 as a permanent default on most phones — you must dial it each call.

Blocking your number by default on mobile phones

If you want your number hidden on every call without dialing *67 each time, you can set it as your default through your carrier. The steps differ by carrier and by whether you have an iPhone or Android phone.

On AT&T: Open the Phone app, go to Settings, then look for "Caller ID" or "Show My Number." Toggle it off. On some AT&T plans this is free; on others AT&T charges a small monthly fee. Call AT&T customer service at 611 from your phone to confirm whether your plan includes it.

On Verizon: Open the Phone app, tap More or Settings, find "Caller ID," and toggle "Show My Number" off. Verizon includes this free on most plans. If you do not see the option in the Phone app, call Verizon at 611 and ask them to enable "Anonymous Call Rejection" or "Caller ID Blocking" on your account.

On T-Mobile: Open the Phone app, go to Settings, tap "Caller ID," and turn off "Show My Number." T-Mobile includes this free. If the option does not appear, contact T-Mobile at 611 or through the T-Mobile app to enable it on your account.

On all three carriers, you can usually override the default on a single call by dialing *82 before the number to show your number for that call only, even if your default is blocked.

Blocking your number on internet calling services

If you use Google Voice, Skype, WhatsApp, or another internet calling app, the blocking option is usually inside the app itself, not through your carrier. These services let you choose whether to display your number on a per-call basis or set a default.

Google Voice: Open the app, tap your profile picture, go to Settings, then "Calls." Toggle "Display outgoing caller ID" off. When it is off, recipients see "Unknown" or no number. You can turn it back on for individual calls by toggling it in the moment before you dial.

Skype: Open Skype, go to Settings, tap "Calls," and look for "Caller ID." You can set it to show your Skype name, your phone number, or hide it entirely. The setting applies to all calls until you change it again.

WhatsApp: WhatsApp calls do not display a caller ID in the traditional sense — the recipient sees your WhatsApp contact name. There is no separate caller ID blocking option because WhatsApp does not transmit phone numbers to the recipient the way a regular call does.

When blocking does not work or is not allowed

Some businesses, government offices, and automated systems reject calls from blocked numbers. Banks, hospitals, and government agencies often have policies that require them to see your number before they answer. If you call a blocked number and the line disconnects or you reach a message saying the call cannot be completed, the recipient's system is rejecting blocked calls.

In these cases, you have two options: unblock your number for that specific call (dial *82 if you have blocking set as default, or turn off the setting temporarily in your app), or call from a different phone. If you need to call a bank or government office and your number is blocked by default, unblock it for that call — these institutions need your number to verify your identity anyway.

Some people also use caller ID blocking to avoid harassment or unwanted contact, but be aware that blocking your number can make it harder for legitimate calls to reach you. If you are expecting a callback from a doctor's office or a business, unblock your number temporarily so they can reach you.

What blocking does not protect you from

Blocking your caller ID hides your number from the person you call, but it does not hide it from your phone company, from law enforcement, or from the phone network itself. If someone takes legal action against you or reports you to police, your real number can be obtained through a court order or subpoena. Phone companies keep records of all calls, blocked or not.

Blocking also does not prevent call tracing or spoofing detection. If someone is harassing you and you block your number, that does not stop them from using other numbers to reach you — it only hides your number from that particular call. If you are being harassed, blocking your caller ID is not a substitute for reporting the harassment to your carrier or to police.

Similarly, blocking your number does not make you untraceable for spam or scam purposes. If you use a blocked number to call someone and they report you as spam, your carrier can still identify you. Blocking is meant for privacy in normal situations, not for evading accountability.

Frequently Asked Questions

Does *67 work on all phone carriers?

*67 works on most major carriers like AT&T, Verizon, and T-Mobile, but not on all plans or all carriers. Some prepaid plans, regional carriers, and older phone systems do not support it. The only way to know is to try it with a test call. If it does not work, you will hear a message or the call will fail.

Can I block my number on calls to 911?

No. Emergency services require your real number and location to respond. If you dial 911 with a blocked number, the system will still transmit your real number to the dispatcher. You cannot block your caller ID on emergency calls.

If I block my number, can the person I call still trace it?

The person you call cannot trace it themselves, but law enforcement can obtain your number through a court order. Your phone company has a record of every call you make, blocked or not. Blocking only hides your number from the recipient, not from the phone system or authorities.

Why do some businesses hang up when I call with a blocked number?

Many businesses and government offices have automated systems that reject blocked calls as a security measure. Banks, hospitals, and customer service lines often need to see your number to verify your identity or to call you back. If a business rejects your blocked call, unblock your number for that call and try again.

Does blocking my caller ID stop spam or scam calls from reaching me?

No. Blocking your outgoing caller ID does not affect incoming calls. If you want to block incoming calls from specific numbers, that is a different feature — usually called "block this caller" or "do not disturb." Check your phone's settings or contact your carrier for options to block incoming calls.