What blocking your number means and why you might do it
Blocking your number means hiding your phone number from the person you are calling so their phone displays "Unknown," "Private," or "Blocked" instead of your digits. When you block your number, the recipient cannot see who called them and cannot call you back using that number — though they can still answer and hear you speak.
People block their numbers for different reasons. You might hide your number when calling a business to avoid getting added to marketing lists, when reaching out to someone you do not know well, or when making a call you prefer to keep private. Some workplaces require employees to block their numbers for security or confidentiality reasons.
Blocking is different from blocking a contact. When you block a contact in your phone's settings, that person cannot reach you at all. When you block your outgoing number, you are controlling what appears on their end when you call them.
Key Takeaways
- Most phones let you block your number on a per-call basis by dialing *67 before the number, or you can set it as a default in your phone settings.
- iPhone users go to Settings > Phone > Show My Caller ID and toggle it off; Android users find similar settings under Phone > Settings > Caller ID or Supplementary Services.
- Blocking your number works on most calls but may not work when calling toll-free numbers, emergency services, or banks — those systems often override the block.
- The person you call cannot see your number, but they can still answer and hear you, and they may be more likely to hang up on an unknown caller.
How to block your number on a single call
The quickest way to hide your number for one call is to use a code before dialing. On most phones in the United States and Canada, dial *67 before entering the phone number you want to call. For example, if you are calling 555-123-4567, you would dial *67-555-123-4567 or *67 555-123-4567 depending on your phone's format.
After you dial *67, your number will be blocked for that single call only. Your next call will show your number normally unless you dial *67 again. This method works on landlines and most mobile phones, though some carriers or phone systems may not support it.
If *67 does not work on your phone, try *141 or #31# depending on your carrier and location. Your phone company's customer service can tell you which code works for your specific service.
How to block your number by default on iPhone
To hide your number on all outgoing calls from an iPhone, open Settings and scroll down to find Phone. Tap Phone, then look for Show My Caller ID. Toggle this setting off, and your number will be blocked on every call you make going forward.
If you turn off Show My Caller ID, callers will see "Unknown" or "Private" instead of your number on every call. You can turn it back on at any time by returning to the same setting and toggling it on. This change affects only your outgoing calls, not incoming ones.
Some carriers may not support this setting, or it may appear in a slightly different location depending on your iPhone model and iOS version. If you cannot find it under Phone settings, contact your carrier to confirm they support caller ID blocking.
How to block your number by default on Android
On Android phones, the process varies slightly by manufacturer and carrier. Start by opening the Phone app and look for a menu icon (usually three dots or lines). Tap Settings, then look for options labeled Caller ID, Show My Number, Supplementary Services, or Call Settings.
Once you find the caller ID setting, select the option to hide or block your number. The exact wording depends on your phone and carrier — you might see "Hide Number," "Block Caller ID," or "Show as Unknown." After you change this setting, your number will be blocked on all outgoing calls.
If you cannot find this setting in the Phone app, check your carrier's website or contact their customer service. Some carriers manage caller ID blocking through their own apps or online account portals rather than through the phone's built-in settings.
When blocking your number does not work
Blocking your number does not work on all types of calls. When you call emergency services (911 in the United States), your number will always be transmitted to the dispatcher regardless of any block you have set. This is a safety requirement so emergency responders can locate you if the call is disconnected.
Toll-free numbers (those starting with 800, 888, 877, or 866) often override caller ID blocks because the businesses receiving those calls have systems designed to capture caller information for service and billing purposes. Banks and financial institutions also frequently bypass blocks when you call them, since they need to verify your identity.
Some older phone systems and private business phone lines may not recognize or respect caller ID blocks. If you are calling a small business or older organization and your block does not work, there is no technical fix — the system straightforward does not support the feature.
What the person you call will experience
When you block your number, the person receiving your call will see "Unknown," "Private," "Blocked," or "No Caller ID" on their phone screen instead of your name or number. They can still answer the call and hear you speak normally. The block only hides your identity; it does not prevent them from picking up.
Many people are cautious about answering calls from unknown numbers, so blocking your number may increase the chance they do not pick up. If you need them to answer, you might want to send a text or email first to let them know you are calling, or explain why you are blocking your number when they do answer.
The person you call cannot use their phone's call-back feature to reach you, since there is no number to call back. If they want to contact you, they would need to know your number through another method or ask you for it during the call.
Blocking your number versus other privacy options
Blocking your outgoing number is different from other privacy features on your phone. Do Not Disturb silences incoming calls and notifications but does not hide your number when you call others. Blocking a contact prevents a specific person from reaching you, but does not hide your number from people you call.
If you want more privacy than blocking your number provides, you could use a second phone number or virtual phone service like Google Voice, which gives you a separate number that forwards to your real phone. This approach lets you keep work and personal calls separate, or use a temporary number for situations where you do not want to share your real one.
For the most privacy, some people use a calling app like WhatsApp or Signal that encrypts calls and does not transmit your phone number to the recipient — they see only your name or username in the app. These options require the other person to have the same app installed.
Frequently Asked Questions
Can someone trace my number if I block it?
No, not through normal means. When you block your number, the recipient cannot see it on their phone screen and cannot use standard call-back features to reach you. However, law enforcement and phone companies can still trace blocked calls if they have a legal reason to do so, such as investigating harassment or a crime.
Will blocking my number prevent spam filters from catching my call?
Possibly. Some spam-detection systems flag calls from unknown or blocked numbers as suspicious, which might cause your call to go to voicemail or be rejected. If you are calling a business or service that uses aggressive spam filtering, blocking your number could backfire and prevent them from answering.
Does blocking my number work on text messages?
No. Blocking your number only affects voice calls. Text messages always show your phone number or contact name to the recipient, and there is no standard way to hide it. If you need to send a private text, you would need to use a messaging app like Signal or a temporary number service.
What if I block my number and the person calls me back?
They cannot call you back using the blocked number because they never saw it. If they want to reach you, they would need to ask for your number during the call or contact you through another method. Your regular phone number is still active and can receive calls normally.
Can my phone company see my number even if I block it?
Yes. Your phone company always knows which number is making a call, even if you block it from the recipient. The block only hides your number from the person you are calling, not from your carrier's systems or records.