You can block your number on a per-call basis or set it as your default

Blocking your number from caller ID means the person you call sees "Unknown" or "Private Number" instead of your phone number. You have two ways to do this: block it for every call you make, or block it just for specific calls. The method depends on your phone type and your carrier.

On most phones, you can add a code before dialing to block that single call. You can also ask your carrier to hide your number on all outgoing calls. Some carriers charge a small monthly fee for this service, while others include it free. The blocking happens at the carrier level, not on your phone itself — your carrier is what controls what information gets sent to the person you're calling.

Key Takeaways

  • Dial *67 before the phone number on most landlines and cell phones in the United States to block your number for that call only.
  • Your carrier can set your number to block by default on all calls, though some carriers charge a monthly fee and others offer it free.
  • Blocking your number does not prevent emergency services from seeing it — 911 calls always show your number regardless of your settings.
  • Some businesses and government offices reject calls from blocked numbers, so you may need to unblock for those calls.
  • Text messages cannot be blocked the same way — you would need to use a separate texting app or service to hide your number when messaging.

How to block your number on a single call

On most phones in the United States, dial *67 before the phone number, then press call. The person who answers will see "Unknown" or "Private Number" instead of your number. This works on both cell phones and landlines, and it blocks just that one call — your next call will show your number normally unless you use *67 again.

The code works the same way whether you're calling from an iPhone, Android phone, or a traditional landline. Type the code, then the full phone number including the area code, then press the call button. If the call doesn't go through, your carrier may not support per-call blocking, or you may have reached a service that rejects blocked calls.

Some carriers outside the United States use different codes. In Canada, the code is *67. In the United Kingdom, it is 141. If you're calling from a different country, check with your carrier for the correct code.

Setting your number to block on all calls

To block your number by default on every call, contact your carrier directly. Call their customer service number (usually on your bill or their website), and ask to enable caller ID blocking or request to have your number withheld. The carrier will make the change on their end, and from that point forward, all your outgoing calls will show as blocked unless you specifically unblock them.

Some carriers offer this service free, while others charge $1 to $5 per month. Ask about the cost before you request it. Once it's turned on, you can still show your number on specific calls by dialing *82 before the number (in the United States). This reverses the block for just that call, which is useful if you're calling a business that won't accept blocked numbers.

The carriers' names for this service vary. Verizon calls it "Caller ID Blocking," AT&T calls it "Calling Line ID Restriction," and T-Mobile calls it "Caller ID Block." The function is the same regardless of the name.

Why some calls still show your number

Emergency calls to 911 always display your number, even if you have blocking turned on. This is required by law so emergency responders can locate you. Your number is also visible to your carrier and to law enforcement if they have a warrant, even when blocking is active.

Some businesses, banks, and government offices automatically reject calls from blocked numbers because they use systems that require caller ID to process the call. If you need to reach one of these places, you'll need to unblock your number for that call by using *82 (if you have default blocking on) or straightforward not using *67 (if you block on a per-call basis).

What caller ID blocking does and doesn't do

Blocking your number hides only the phone number itself. It does not hide your voice, your name if you say it, or any other information you provide during the call. The person you call will still hear everything you say and can record the conversation (depending on local recording laws). Blocking is useful for privacy, but it is not the same as anonymity.

Caller ID blocking also does not prevent the person from calling you back or looking up your number through other means. If you call someone and then hang up, they may be able to see your number in their phone's recent calls or through their carrier's records, depending on their service. Blocking only affects what shows on their caller ID display at the moment of the call.

Blocking your number on text messages

Standard text messages (SMS) cannot be blocked the same way phone calls can. Your number will always appear on a text message you send through your carrier's normal texting service. If you need to send a text without showing your number, you can use a third-party texting app like Google Voice, Signal, or WhatsApp, which use internet data instead of your carrier's SMS system.

These apps let you create a separate phone number or use an existing number, and the recipient sees the app's number or your chosen number instead of your actual phone number. However, the recipient must have the same app installed to receive the message, or you must be using a service like Google Voice that can send to regular phone numbers.

When blocking your number might cause problems

Some services will not complete a call from a blocked number. Banks, credit card companies, and insurance companies often have automated systems that require caller ID to verify your identity. If you call with your number blocked, the system may hang up or transfer you to a representative who cannot help you without unblocking.

Employers, schools, and medical offices may also ignore or reject blocked calls. If you're calling to schedule an appointment or reach someone for work, unblocking your number usually gets better results. You can always unblock for that specific call using *82, or straightforward not use *67 if you normally block on a per-call basis.

Frequently Asked Questions

Does *67 work on all phones?

*67 works on most landlines and cell phones in the United States, but some carriers or phone plans may not support it. If the code doesn't work, contact your carrier to confirm they offer per-call blocking. International carriers use different codes — check with your provider if you're outside the US.

Can someone trace a blocked number?

The person you call cannot trace a blocked number from their end. However, your carrier has a record of the call, and law enforcement can obtain that information with a warrant. Blocking hides your number from the recipient, not from your carrier or the legal system.

Will blocking my number prevent spam calls to me?

No. Blocking your outgoing number does not affect incoming calls. To reduce spam calls, use your phone's built-in call blocking feature, enable "Filter Unknown Senders" (on iPhone) or "Spam Protection" (on Android), or contact your carrier about their spam-blocking service.

What's the difference between *67 and *82?

*67 blocks your number for a single call. *82 unblocks your number for a single call if you have default blocking turned on with your carrier. If you don't have default blocking, *82 does nothing — your number will show normally anyway.

Can I block my number on a conference call?

If you initiate the conference call, your number will show to all participants unless you have default blocking on. If you're joining a conference call someone else started, using *67 before dialing the conference number may block your number, but some conference systems override blocking. Test it with a non-critical call first.