How to Block a Number When Calling: A Simple Guide

There are two very different things people mean when they search for how to block a number when calling. The first is hiding your own number so it shows up as “Unknown” or “Private” on the other person’s phone. The second is stopping a specific number from ever reaching you in the first place. Both are common needs, and both are easy to mix up because they share the same word: block.

This post covers the first meaning in depth, hiding your caller ID when you place a call, and then touches on the second so you leave with a complete picture. We will walk through iPhone, Android, carrier codes, and what happens when you run a business phone system where caller ID does more than just show a name.

What Does “Blocking Your Number When Calling” Actually Mean?

When you block your number on an outgoing call, you are withholding your caller ID. The person you dial still receives the call, but their screen shows something like “No Caller ID,” “Private,” “Unknown,” or “Blocked” instead of your actual phone number. Your identity is hidden for that call, but the call itself goes through normally.

This is different from blocking someone from calling you, which stops their calls from reaching your phone at all. People often type “how to block a number when calling” when they mean either one, so it helps to be clear about which you want before you change any settings. Hiding your caller ID is a privacy choice you make about your outgoing calls. Blocking an incoming caller is a filter you apply to keep someone out.

Below we cover how to hide your number, per call and permanently, then explain the incoming side so both bases are covered.

How to Block Your Number on iPhone

Apple lets you hide your caller ID for every outgoing call with a single setting. Here is how to turn it on:

1. Open the Settings app.
2. Scroll down and tap Phone.
3. Tap Show My Caller ID.
4. Toggle the switch off.

With that switched off, every call you place will show up as hidden on the recipient’s phone. If you do not see the Show My Caller ID option, your carrier may not support the toggle, in which case you can use a per-call code instead (covered further down). Turning the toggle back on restores your normal caller ID.

One note: this setting only affects standard phone calls. It does not hide your identity on FaceTime, iMessage, or third-party calling apps, which have their own privacy controls.

How to Block Your Number on Android

Android varies by manufacturer, but most phones keep the caller ID setting inside the Phone app:

1. Open the Phone app.
2. Tap the three-dot menu in the top right corner.
3. Tap Settings, then look for Calling accounts or Supplementary services.
4. Tap Show your caller ID (wording varies) and choose Hide number.

On Samsung phones, the path is often Phone app > Settings > Supplementary services > Show your caller ID > Hide number. On Google Pixel phones, look under Settings > Calling accounts > your SIM > Additional settings > Caller ID. If your version of Android buries the option or hides it entirely, the per-call method below works on almost any phone regardless of make.

How to Hide Your Number on a Single Call

Sometimes you do not want to hide your number all the time, just for one specific call. Most carriers support a dialing prefix that blocks your caller ID for that one call only, leaving your normal settings untouched afterward.

In the United States and Canada, dial *67 before the number. So if you wanted to call 555-123-4567 with your number hidden, you would dial *67 555 123 4567. The recipient sees “Private” or “Blocked” for that call, and your next call goes out normally with your caller ID showing.

Other countries use different codes. In the UK, the prefix is 141. In Australia, it is 1831. If the standard code does not work, your carrier’s support line can confirm the right one for your region and plan. Keep in mind that certain recipients, such as emergency services and some toll-free business lines, can still see your number regardless of the prefix.

Why Won’t My Blocked Number Stay Hidden?

If you set your phone to hide your caller ID but the recipient still sees your number, a few things could be happening. The most common cause is that your carrier overrides the device setting, or the setting did not save properly. Toggling it off and on again, then placing a test call to a friend, usually reveals whether it is working.

Another reason is that some business phone systems and toll-free lines are set up to capture the calling number even when caller ID is withheld. These systems can pull the underlying network number for billing or verification purposes, so a hidden caller ID does not guarantee complete anonymity. If true privacy matters, a separate calling app or a dedicated number is a more reliable route than the standard hide-my-number toggle.

Finally, if you dialed a per-call prefix but forgot it on a later call, that later call went out with your number visible. Per-call codes only apply to the single call you use them on, so they need to be dialed every time.

How This Looks From the Business Side

If you run a business, caller ID works in the opposite direction from what most privacy seekers care about. You usually want your number to show clearly so customers recognize and trust the call, and you want to see the numbers of people calling you so you can serve them well and understand where they came from.

That second part is where things get interesting. When a customer hides their caller ID and calls your business, you see “Unknown” or “Private” instead of a real number. On a personal phone, that is just an anonymous call. On a business phone system, it can mean a lost opportunity to understand your lead, because you cannot tie that call back to an ad, a search, or a campaign.

This is exactly the problem call tracking is built to solve. Instead of relying on the raw caller ID, a call tracking platform assigns unique numbers to your marketing sources and records which number a caller dialed. Even if a caller hides their own ID, you still know which ad, page, or campaign drove the call. Understanding how call tracking works shows why that source data is often more valuable than the caller’s actual phone number.

Caller ID also matters for the outbound side of a business. When your team places calls, the number that appears on the customer’s screen affects whether they answer. Businesses that use outbound call tracking can control and monitor which numbers show on outgoing calls, which is the reverse of an individual quietly hiding a personal number. The goal for a business is usually visibility and consistency, not anonymity.

How to Block Someone From Calling You

Since many people search for “how to block a number when calling” but actually want to stop an incoming caller, here is the short version of that too.

On iPhone, open the Phone app, tap the i next to the number in your recent calls, scroll down, and tap Block this Caller. On Android, open the Phone app, tap and hold the number in your call log, and choose Block or Block/report spam. Both methods stop that number from reaching you by call or text.

You can also block numbers through your carrier’s spam-protection tools or, for a business, inside your phone system’s admin dashboard. Blocks can live in more than one place, so if a caller still gets through after you block them, check your device, your carrier account, and any business system separately.

Frequently Asked Questions

Does *67 work on every phone?

The *67 prefix works on most mobile and landline phones in the United States and Canada, regardless of make or model, because it is a network feature rather than a device setting. That said, some carriers and calling plans do not support it, and certain recipients like emergency services or specialized business lines can still see your number. If the code does not seem to hide your caller ID, place a test call to a friend and, if it still shows, contact your carrier to confirm whether the feature is available on your plan.

Will the person know I blocked my number when I called?

They will know a call came in from a hidden number, because their screen shows “Private,” “Unknown,” or “No Caller ID” instead of your actual number. What they will not see is who you are. Hiding your caller ID does not send any special alert, it simply withholds your identity. Many people let unknown numbers go to voicemail, so hiding your number can mean fewer of your calls get answered.

Can a business still see my number if I block it?

Sometimes, yes. While a hidden caller ID stops your number from displaying on a normal phone, some business systems can capture the underlying network number for billing or verification. A call tracking platform focuses more on which number you dialed than on your personal caller ID, so a business often still learns useful information about the call even when your ID is hidden. If complete anonymity matters to you, a hidden caller ID alone is not a guarantee.

What is the difference between hiding my number and blocking a caller?

Hiding your number applies to calls you make: your caller ID is withheld so the recipient cannot see who is calling, but the call still goes through. Blocking a caller applies to calls you receive: their number is filtered out so it never reaches your phone. They share the word “block,” but they work in opposite directions. Decide which one you want before changing settings, because the menus and steps for each are completely separate.

The Bottom Line on Blocking Your Number When Calling

To hide your number on outgoing calls, use the caller ID setting on your phone (Settings > Phone > Show My Caller ID on iPhone, or the Phone app settings on Android) for a permanent change, or dial *67 before the number for a single call. If your number still shows, your carrier may not support the setting, so a test call and a quick support check will confirm it.

If you landed here wanting to stop someone from calling you instead, that is a separate feature found in your phone’s call log or block list. And if you run a business, the caller ID story flips: you usually want your number visible and want to see who is calling. Pairing clear caller ID with solid call tracking gives you the source data that matters, even when a caller chooses to hide their own number.