Hide Outgoing Caller ID (Prefix Star Codes)
To hide your number for one call in the United States, many phone services support dialing *67 before the full number. The recipient may see “Private” or similar, but the wording varies. The code depends on your carrier and country, and it does not make a call anonymous. Confirm your provider’s instructions and test the feature first.
Think of caller ID as a name tag sent with a call. A prefix such as *67 asks many U.S. phone services not to show your number to the person you call. It changes what the recipient usually sees; it does not erase the call or hide your identity from your carrier.
I treat this as a carrier feature, not a universal phone setting. The right steps depend on where you are, how your line works, and whether you already have caller-ID blocking. Here is how to check, use, and test the feature without assuming one code works everywhere.
Planning — Intent and rules
Per-call blocking is meant to suppress caller-ID display for one call, not to change your account’s default setting. In the United States, *67 is a common prefix for this purpose. Carrier rules and country dialing plans differ, so confirm the code with your phone provider before relying on it.
Caller ID is the number or name shown on a receiving phone when a call comes in. Per-call blocking asks the service to withhold that display information for a single call. In many U.S. cases, you dial *67 immediately before the destination number.
The Federal Communications Commission’s rules at 47 CFR § 64.1601 address caller-identification information and related privacy practices. The practical dialing instructions still come from your carrier. A code that works on one type of line, or in one country, may not work on another.
Keep these limits in mind:
- A prefix usually applies only to the call that follows it. It does not normally change your line’s default caller-ID setting.
- A recipient may see “Private,” “Blocked,” “No Caller ID,” or another label. The exact display depends on the phone service and device.
- Blocking caller ID is not anonymity. Your carrier may retain call records, and some services may receive calling-number information.
- Do not use caller-ID blocking for threats, harassment, fraud, or other unlawful conduct.
The first step is simple: identify your country and provider, then check the provider’s current instructions for your line.
Access — Check your carrier and device
A carrier is the company or service that connects your calls, such as a mobile, landline, or VoIP provider. VoIP means phone service carried over an internet connection. Before dialing a prefix, confirm your line type and whether blocking is already set on the account.
Look for caller-ID or outgoing-call privacy settings in your carrier’s account tools, help pages, or support instructions. Phone menus can also vary by model and software version, so a setting on a handset may not control what the carrier sends.
| Check | What to find out | Why it matters |
|---|---|---|
| Country | Where your service is based | Prefixes vary by country |
| Line type | Mobile, landline, or VoIP | Support may differ by service |
| Carrier instructions | Current code and dialing format | The carrier controls whether it works |
| Default setting | Whether permanent blocking is enabled | This affects when *82 may be useful |
| Destination | Whether it is an ordinary number, emergency service, or toll-free service | Blocking may not work as expected for some destinations |
Do not assume that a code from a search result applies to your line. For example, #31# is used in some places or services, but that does not make it the right code for every U.S. carrier. If the provider’s instructions are unclear, ask support before testing.
Execution — Apply the prefix
For a typical U.S. call with per-call blocking, dial *67 followed immediately by the full destination number. Use the same number format you normally use for that call. The prefix should affect that call only, but carrier instructions take priority.
A practical sequence is:
- Confirm the code. Check your provider’s current instructions for your country and line type.
- Enter the call. On a typical U.S. line, dial
*67and then the full destination number, with no pause between the prefix and number. - Place the call. Follow any prompts from your service. Do not assume the call is blocked just because it connects.
- Check the result. If suitable, ask a consenting recipient what appeared on their caller-ID display.
- Stop if it fails. Use your provider’s settings or contact support rather than trying codes from another country or service.
If permanent caller-ID blocking is enabled on a line, *82 is a common U.S. code used to release caller-ID information for a particular call. That use is different from blocking a single call with *67. Confirm the exact format with your carrier before using either prefix.
Verification — Test results and exceptions
A test call checks what the recipient’s phone actually displays. It does not prove that your number is hidden from every party involved in the call. Test with a person who agrees to help and has caller ID enabled, then check the result before relying on the feature.
If the recipient sees your number, the prefix may not be supported, may have been entered in the wrong format, or may work differently on that line. Ask your carrier which of those applies. A successful call alone is not proof that blocking worked.
A recipient may also choose not to accept calls marked private or blocked. That is their device or service behavior, and it may prevent you from reaching them. If the call is important, use a method the recipient accepts rather than repeatedly calling from a blocked line.
Caller-ID blocking generally does not prevent number or identity delivery to emergency services or toll-free services that receive calling-number information. Do not use a prefix to conceal information from emergency responders or to assume a toll-free call cannot be traced. Carrier records may also remain available even when the recipient’s display is blocked.
Use cases and code comparison
These examples are practical scenarios, not reports of specific people or verified case studies. They show how I would choose a next step when someone asks about a private call: verify the line, use only the provider’s supported prefix, and check the result with a consenting recipient.
| Need | Common U.S. option | Scope | What to verify |
|---|---|---|---|
| Hide the display for one call | *67 before the number | Usually one call | Carrier support and recipient display |
| Send caller ID on one call from a line with permanent blocking | *82 before the number | Usually one call | Whether permanent blocking is active and the carrier’s format |
| Change the line’s usual caller-ID behavior | Carrier account setting or support | May affect future calls | What setting changes and how to reverse it |
| Use a prefix outside the United States | No universal code | Depends on country and provider | Local carrier instructions |
For example, if you want to make one ordinary call from a U.S. mobile line, first confirm that your carrier supports *67, then test it with someone you know. If you manage a VoIP line for a small business, check that provider’s documentation instead of assuming the same prefix works.
If *67 does not work, do not jump to another code based only on a forum post. Confirm the line type and dialing format with your provider. If you use *82, verify that your account has permanent blocking enabled and that your carrier supports releasing caller ID on a per-call basis.
Conclusion and FAQ
The reliable approach is to check your carrier’s instructions, apply the supported prefix to the call, and test the display. In many U.S. services, *67 blocks caller-ID display for one call, while *82 may release it for one call from a line with permanent blocking. Neither code makes a call anonymous.
Does *67 work on every phone?
No. It is common in the United States, but support depends on the carrier, country, and line type.
How do I dial *67?
For a typical U.S. call, dial *67 followed immediately by the full destination number. Confirm your carrier’s format first.
Does *67 block my number for all future calls?
Usually not. It commonly applies only to the call preceded by the code. Permanent settings are separate.
What does the recipient see?
They may see “Private,” “Blocked,” “No Caller ID,” or similar wording. The display varies by carrier and device.
What does *82 do?
It is a common U.S. code for sending caller-ID information on a call when permanent blocking is enabled. Check with your provider before using it.
Will caller-ID blocking hide my number from my carrier?
No. Blocking the recipient’s display does not mean the carrier lacks call records or calling-number information.
Does *67 work for emergency calls?
Do not rely on it to hide your number from emergency services. Emergency services may receive calling-number information.
Can I use *67 for toll-free calls?
Blocking may not prevent toll-free services from receiving calling-number information. Check your carrier’s guidance.
What if the prefix does not work?
Stop and check the carrier’s current instructions or contact support. Do not assume a code used in another country will work.
Can a person reject a blocked call?
Yes. Some phones or services can reject calls marked private or blocked, so the call may not reach the recipient.
(This article was written by one of our staff writers, Richard Montclair. Visit our Meet the Team page.)
