What blocking your number actually does

When you block your number, you hide your phone number from appearing on the recipient's caller ID. Instead of seeing your digits, they see "Unknown," "Private," or "Blocked" — depending on their phone and carrier. The call still goes through normally; they can answer it, hear you, and talk back. You are not preventing the call from reaching them. You are just hiding the identity attached to it.

This is different from blocking a contact, which prevents someone from calling or texting you at all. Blocking your number is about what you send out; blocking a contact is about what you receive.

Key Takeaways

  • Blocking your number hides your caller ID but does not stop the call from going through — the recipient can still answer and hear you.
  • You can block your number per call using *67 on most landlines and many cell phones, or you can set it as the default for all outgoing calls in your phone settings.
  • Some carriers charge a monthly fee for a permanent block, while the per-call method (*67) is free but must be entered each time.
  • Blocking your number does not work on emergency calls (911), toll-free numbers, or some business lines that have caller ID blocking disabled.
  • The recipient may still be able to see your number if they use a service that unblocks hidden numbers, though this is uncommon for personal calls.

The *67 method for blocking one call at a time

The simplest way to block your number on a single call is to dial *67 before the phone number you are calling. On most landlines and many cell phones, this tells your carrier to hide your caller ID for that one call only. You dial it the same way you would dial any other number — *67, then the area code and phone number.

After you hang up, your number is visible again on the next call you make. You have to enter *67 each time you want to block it. This method is free on most carriers and works on both iPhone and Android phones, though some carriers or phone plans may not support it.

The timing matters: dial *67 first, then the number. If you dial the number first and then try to add *67, it will not work.

Setting your number to block by default

If you want your number hidden on every call you make, you can change this in your phone's settings rather than entering *67 each time. On an iPhone, go to Settings, then Phone, then Show My Caller ID — toggle this off. On Android, the location varies by phone model and carrier, but it is usually in Settings, then Call Settings or Similar, then Caller ID, and you select "Hide Number" or turn off "Show Caller ID."

Once you change this setting, your number will be blocked on all outgoing calls unless you turn it back on. Some carriers also let you manage this through their website or customer service line, and a few charge a monthly fee (usually $2 to $5) for this feature, though many do not.

Check with your carrier before assuming the feature is free. Call their customer service number or log into your account online to confirm whether blocking your number by default costs anything on your plan.

When blocking your number does not work

Blocking your number fails on emergency calls. If you dial 911, your number will be sent to the dispatcher regardless of whether you have *67 active or your caller ID blocked in settings. Emergency services need to know where the call is coming from.

Toll-free numbers (those starting with 800, 888, 877, or 866) often cannot receive blocked calls at all — the call may not go through, or it may go through but the business will see a generic "blocked" message instead of your number. Some business lines, customer service centers, and government offices have caller ID blocking disabled on purpose, so your number will show even if you tried to hide it.

Additionally, some third-party services can unmask blocked numbers, though these are uncommon for personal calls and more often used by businesses or law enforcement.

Why someone might block their number

People block their numbers for many reasons. You might not want a business to have your personal number when calling about a service. You might be calling someone you do not know well and prefer not to share your number on a first contact. You might be concerned about your number being added to marketing lists or sold to other companies.

Some people block their number out of habit or privacy preference, even when there is no specific reason. Others use it when calling a business during a dispute, so the business cannot call them back repeatedly.

Blocking your number does not make you anonymous — if the person answers and you speak, they will know who you are by your voice. It only hides the number itself from their caller ID.

The difference between blocking your number and other privacy options

Blocking your number is not the same as using a VoIP service (Voice over Internet Protocol), which routes calls through the internet instead of traditional phone lines and can mask your location. It is also different from a burner phone or temporary phone number, which gives you a completely separate number that you can discard later.

If you need more privacy than blocking your number provides — for example, if you want a separate number for a specific purpose that you can later abandon — those options exist but require setting up a different service or phone. Blocking your number is the quickest, free option for hiding your caller ID on calls you make from your regular phone.

Frequently Asked Questions

Does blocking my number prevent someone from calling me back?

No. Blocking your number only hides your caller ID on outgoing calls. It does not affect incoming calls or prevent someone from reaching you. If you want to prevent someone from calling you, you need to block their contact in your phone instead.

Can someone trace a blocked number?

Not easily. A private person cannot see a blocked number from their caller ID. Law enforcement and emergency services can access blocked numbers if needed, but a regular person cannot trace a hidden number just by looking at their phone.

Will *67 work on my cell phone?

It works on most cell phones, but not all carriers support it. Try dialing *67 before a number on a test call to see if it works on your plan. If it does not, your carrier may not offer the feature, or you may need to enable it in your account settings first.

What happens if I block my number and call a business?

The business will see "Unknown" or "Blocked" instead of your number. Some businesses may not answer calls from blocked numbers, or they may answer but ask you to unblock your number before they can help you. Toll-free numbers especially may reject blocked calls entirely.

Does blocking my number hide my location?

No. Blocking your number hides only your phone number from caller ID. Your location data is separate and is not hidden by this feature. If someone has access to your location through other means (GPS, phone tracking apps, or your carrier's location services), blocking your number does not change that.