Hide Phone Caller ID on Outgoing Lines (*67 Prefix)

To block your number from appearing on one supported U.S. outgoing call, dial *67 immediately before the full destination number. This is per-call caller-ID blocking, not a permanent setting or anonymity: your carrier may still identify the line, and emergency, toll-free, or other services may handle caller information differently. Check carrier support before relying on it.

As holiday calls, seasonal appointments, and other one-off contacts pick up, you may want to reach someone without sharing your number. The *67 prefix can help with that on supported U.S. phone services. It changes what caller ID is presented to the person you call; it does not hide your identity from the phone network.

I treat caller-ID blocking as a narrow privacy setting, not a security tool. Before dialing, check that your service supports the prefix and consider whether the recipient needs your number to return the call. These simple checks can prevent confusion and help you use the feature for the right calls.

Planning: Confirm Carrier and Service Support

Per-call blocking tells a supported phone service not to present your number to the person receiving that call. In the United States, *67 is the standard prefix on supported services. Carrier rules and device behavior can vary, so check your mobile, landline, or VoIP provider if the feature matters for a specific call.

The federal caller-ID rule, 47 CFR §64.1601(b), addresses the availability of calling-party-number blocking on covered services. It does not mean every phone system handles the feature in the same way. A mobile carrier, home phone provider, business phone system, or internet calling service may have its own instructions or limits.

Before using the prefix, confirm:

• Your carrier supports per-call caller-ID blocking with *67.
• The feature works on the line you plan to use, especially if it is a business or VoIP line.
• Your plan or device does not apply a separate caller-ID setting that changes the result.
• You know how to reach the recipient if they do not answer blocked calls.

A useful check is to ask the carrier: “Does *67 block my caller-ID number for one outgoing call on this line?” If the answer is unclear, ask whether there is a different per-call code or a setting in the account or phone app.

Next step: Confirm support before testing the prefix on a time-sensitive call.

Access and Clearances: Check Number Format and Call Type

The number format is the complete number your phone service needs to place the call. Add *67 directly before that number, including the area code and any required dialing digits. The prefix is meant for a single call, and some services may not accept it for every destination or call type.

For a domestic call, enter *67 followed by the number in the format your carrier requires. For example, if the number is 212-555-0148, the dial string would be *672125550148. Do not add a pause between the prefix and number unless your provider specifically instructs you to do so.

Check the call type as well:

• Emergency calls: Do not rely on caller-ID blocking when calling 911. Emergency systems may receive or derive caller information, and the call must not be delayed by privacy settings.
• Toll-free calls: Blocking generally does not conceal the number from toll-free services. Network rules and service handling can allow the receiving system to identify a caller.
• International calls: Prefix behavior and number formats vary. Check with your provider rather than assuming the U.S. code will work.
• Business or internet phone systems: A company phone system may change, reject, or override the prefix.

A recipient’s phone may show “Private,” “Blocked,” “No Caller ID,” or another label. The exact wording depends on the carrier and device, so the display label alone does not prove how the call was handled behind the scenes.

Next step: Use the number format required by your carrier and avoid this method for emergency or confidential communications.

Execution: Apply the Per-Call Prefix

To place a blocked call, enter *67 before the full destination number and start the call. The setting applies to that call only on supported services. For a later call where you want your number shown, dial normally unless your carrier tells you otherwise.

Use this sequence:

1. Open your phone’s dial pad.
2. Enter *67 followed immediately by the full number.
3. Check the digits before placing the call.
4. Tap or press the call button.
5. For a later call that should show your number, dial without the prefix.

You can type the number manually or edit a saved contact number for that call. If you use a contact shortcut, confirm that your phone has not removed the prefix or substituted a different number. A saved contact may also contain country codes, pauses, or extension instructions that affect how the call is placed.

Do not assume a carrier-specific “unblock” prefix works everywhere. The simplest way to make a later call normally is to dial the number without *67. If your service uses a different method, follow the carrier’s instructions.

Next step: Use the prefix only on the individual call where you want caller-ID presentation blocked.

Verification: Confirm Display Behavior and Limits

Verification means checking whether the recipient’s phone displays your number or a blocked-caller label. It can show whether the feature appears to work at the receiving end, but it cannot prove that the call is anonymous or that no network can identify the line.

If it is appropriate, test with someone you know before using the feature for an important call. Ask what appeared on their screen. A blocked label is the expected general result, but the wording varies, and some people or organizations do not accept calls without caller ID.

If the call does not connect or your number still appears, check these points:

• Confirm that you entered *67 before the full number.
• Check for a typing error or an extra character in the dial string.
• Ask whether your carrier supports the code on that line and for that call type.
• Check whether a business phone system or calling app handles the call.
• Contact your provider if the result differs from its stated instructions.

The key limit is important: *67 affects caller-ID presentation. It does not erase call records held by your carrier, prevent lawful tracing, or guarantee that the recipient’s service cannot obtain caller information. Do not use it as a substitute for secure or confidential communication.

Next step: Treat a successful blocked display as limited presentation control, not proof of anonymity.

What to Expect by Phone Service

The table below summarizes common situations. It is a guide to what to ask, not a promise that every carrier or device behaves the same way. Confirm the instructions for your own line before relying on the prefix.

Call setup	What to try	What to confirm
Supported U.S. mobile line	Dial *67 before the full number	Carrier support and any call-type limits
Supported home landline	Dial the prefix before the number	Whether the line accepts the prefix
VoIP or internet calling app	Follow the provider’s instructions	Whether the app supports per-call blocking
Business phone system	Ask the phone administrator or provider	Whether the system passes or overrides the code
911 or other emergency call	Do not rely on caller-ID blocking	Emergency services may receive caller information
Toll-free destination	Do not assume the number is hidden	Toll-free systems may receive caller information

A phone setting that blocks caller ID for all calls is different from a per-call prefix. If you change a global setting, check it afterward so you know whether it affects future calls. For one call, the prefix is useful only when your provider supports it and the call type allows it.

Next step: Match the method to the service, then verify the display when practical.

Illustrative Call Scenarios

These examples are hypothetical. They show how to apply the steps without suggesting that every carrier or recipient will behave the same way.

A homeowner wants to call a local business once without displaying a personal number. They confirm with their mobile carrier that *67 is supported, enter the prefix before the full number, and place the call. If the business does not accept blocked calls, they can choose whether to call normally or use another contact method.

A small business owner calls from a VoIP desk phone and enters the prefix, but the call does not go through. The right next step is not to keep changing codes at random. The owner checks with the phone provider or administrator, since the system may handle prefixes differently from a standard mobile line.

A person wants a later call to show their number after using blocking once. They dial the next number normally, without *67, and check with the recipient if the display matters. Per-call blocking should not be treated as a lasting account change.

Next step: When the outcome matters, confirm the service rules and recipient display rather than guessing.

Conclusion: Use Blocking for Presentation, Not Anonymity

*67 can hide your number from caller-ID display for one outgoing call on supported U.S. services. Enter it immediately before the complete destination number, and dial normally when you want your number presented on a later call. Carrier and call-type limits still apply.

Use the feature for limited caller-ID privacy, not for emergencies or confidential communications. Your carrier may still identify the line, and the receiving service may handle caller information in other ways. When unsure, ask your provider before placing the call.

Frequently Asked Questions

These answers cover the most common questions about using *67. Carrier support and call handling can differ, so confirm details with your provider when the result is important.

Does *67 hide my number for one call or all calls?
On supported services, it blocks caller-ID presentation for that call only. Dial normally on a later call if you want your number shown.

How do I dial *67 correctly?
Enter *67 immediately before the full destination number, using the number format your carrier requires. Then place the call as usual.

What will the person I call see?
They may see “Private,” “Blocked,” “No Caller ID,” or a similar label. The wording depends on their carrier and device.

Can my phone carrier still identify my call?
Yes. Caller-ID blocking limits presentation to the recipient; it does not prevent your carrier from identifying the line or keeping call records.

Does *67 make a call anonymous?
No. It does not guarantee anonymity or prevent lawful tracing. It is a caller-ID presentation feature.

Will *67 work for every mobile carrier?
No. It is standard on supported U.S. services, but support and behavior can vary by carrier, plan, device, or calling app. Check with your provider.

Does *67 work for 911 calls?
Do not rely on it for 911. Emergency systems may receive or derive caller information, and you should not delay an emergency call to change caller-ID settings.

Does it hide my number from toll-free numbers?
Not reliably. Toll-free systems may receive caller information despite blocking. Check the handling rules for the service if needed.

Will my number show on the next call?
Per-call blocking does not normally carry over to the next call. Dial without *67 when you want your number presented, unless your provider says otherwise.

What if the call fails after I enter the prefix?
Check the digits and number format, then confirm that your carrier supports the prefix for that line and destination. A VoIP or business system may use different instructions.

(This article was written by one of our staff writers, Richard Montclair. Visit our Meet the Team page.)