Caller ID is not proof of who is on the line. If you don't recognize the number, let it ring. For U.S. consumers, the routine that still works is simple: send unfamiliar calls to voicemail, turn on the spam tools already on your phone and carrier account, register with the National Do Not Call Registry, and report scams. No filter catches every call. A local area code, a familiar business name, or a voice that sounds like someone you know can all be faked.

Do this first:

  1. Don't answer an unexpected call if you aren't sure who it is.
  2. Let it go to voicemail and see whether the caller gives a specific, verifiable reason for calling.
  3. Turn on your phone's spam protection and your carrier's call-filtering tools.
  4. Register your number at the National Do Not Call Registry to reduce calls from some legitimate telemarketers.
  5. Never send money or share passwords, one-time codes, or other sensitive information because of an unsolicited call.

What counts as a spam call?

People use these words interchangeably, but they aren't the same problem.

A spam call is any unsolicited sales, survey, political, charity, or other unwanted call. A robocall uses an automatic dialer or a prerecorded message; some of those calls are lawful, and some are scams. A scam call is built to steal money, account access, or personal information. A spoofed call shows a caller ID number that isn't the number actually placing the call.

Labeling and blocking also do different jobs. Labeling still lets the call through, but your screen may say "Spam" or "Scam likely." Blocking or screening can stop the ring, send the call to voicemail, or ask the caller to identify themselves. The FTC's guide to blocking unwanted calls covers the main options for cell phones, internet-based home phones, and traditional landlines.

A nearby area code doesn't mean the caller is nearby. A company name on the screen doesn't mean that company placed the call.

How spam calls work

A lot of unwanted calling runs over internet phone service and automated dialers. The system can work through huge number lists, play a recording, and only connect the people who answer to a live operator. Other setups leave a message meant to make you call back.

Spoofing is how those operations get you to look. The display might match your area code, resemble your own number, or copy a bank, delivery company, or government line. If that displayed number gets blocked or reported, the caller can switch to another one.

Some calls use computer-generated or imitated voices. A voice that sounds like a relative or a public official still doesn't prove who is calling. Check the claim through a separate channel you already trust.

Filters miss calls because they have to guess. A brand-new number may not be flagged yet. Crank the setting too high and you can bury a doctor's office, school, delivery driver, or job interview in voicemail.

How to block spam calls on a cell phone

Use the controls already on the phone

Open your call settings and look for options such as:

On Android phones that use Google's Phone app, caller ID and spam protection can name businesses or warn about possible spam. Some compatible devices also offer Call Screen. What you see depends on the phone, software version, and location. Google says turning the feature on may mean information about your calls is sent to Google, so read that setting before you enable it. See Google's caller ID and spam protection guidance.

Add the numbers you actually need to your contacts, and look at your blocked-caller list once in a while. If you silence every unknown number, make sure you have another way to get time-sensitive calls.

Check your carrier's tools

Your wireless provider may offer spam labels, high-risk call blocking, voicemail screening, or category controls in your account or its app. Availability can change with your plan, phone, location, and the type of call. Verizon's Call Filter instructions, for example, say some controls aren't available for every call, device, or area.

Network-level filtering is convenient because it works before the call reaches you. It still isn't a guarantee. After you turn on a strict filter, check voicemail, especially if you expect calls from people who aren't in your contacts.

Consider a call-blocking app

The FTC says blocking software or devices can stop many unwanted calls, including scam calls and illegal robocalls, before they reach you. If you install an app, check four things first:

Skip any service that claims it can identify every scammer or recover money just by tracing a phone number.

How to block spam calls on a home phone

The option that fits depends on the service you have.

Internet-based home phone: Look in the provider's account dashboard or support pages for call screening, anonymous-call controls, and number blocking.

Traditional landline: Ask the phone company which blocking services it offers, or use a compatible call-blocking device.

Shared household line: Keep the setting less aggressive if family members, medical offices, schools, or businesses regularly call from numbers you don't have saved.

Blocking withheld, international, or unfamiliar calls can cut nuisance traffic and also block people you wanted to hear from. If missing a call would be a problem, start with labeling or voicemail screening instead of a hard block.

What the Do Not Call Registry does and doesn't do

The National Do Not Call Registry is meant to reduce sales calls from legitimate telemarketers. It is not a call-blocking service, and it will not hide your number from every caller.

Registration generally doesn't stop scam calls from people who ignore the law, some political or nonprofit calls, calls from a company you already do business with, or calls from businesses or organizations you gave permission to contact you.

You can register up to three numbers at a time online. If the site sends a confirmation email, open it and use the registration link within 72 hours. The FTC's National Do Not Call Registry FAQs cover the process and its limits.

If a company you recognize keeps calling, tell it to stop and keep a record of that request. That company's own do-not-call process is separate from the blocking features on your phone or carrier account.

Common scam call warning signs

Hang up, or don't pick up, if the caller does any of the following:

The IRS warns about government impersonators who demand gift cards and tells taxpayers to verify information through IRS.gov guidance on gift card scams. Use the same habit with banks and other organizations: end the call, then use the number on your statement, card, official app, or a website you found yourself.

You don't have to prove the caller is a scammer while the phone is still in your hand. Don't give information, payment, or a verification code. Don't trust the caller ID or a callback number left in a message. Hang up if the person creates pressure or refuses verification, then contact the claimed organization through an official channel. Block the number and keep the voicemail or other evidence. Arguing, or pressing buttons to "opt out," isn't required. A legitimate caller who needs you should be able to leave enough detail for you to check the request.

If you already shared information or sent money

Use the payment method's own support channel as soon as you can. Recovery isn't guaranteed, and waiting usually shrinks what's left to try.

Save the displayed number, date and time, voicemail, the caller's claimed identity, payment receipts, emails, text messages, and any account alerts.

How to report spam calls and phone scams

A report won't necessarily stop the next call or produce an investigation of your case. Regulators still use those details to spot patterns.

  1. Write down what you have. Note the number on caller ID, the date, approximate time, message, company claimed, requested payment, and any callback number.
  2. Report fraud to the FTC. Use ReportFraud.ftc.gov for scam calls, impersonation, and financial loss.
  3. Report unwanted calls to the FCC. Use the FCC's unwanted calls and texts complaint page. The FCC says it doesn't resolve individual complaints; the information supports enforcement and policy work.
  4. Report an IRS impersonation call. Follow the IRS guidance and include "IRS phone scam" in the FTC report notes.
  5. Describe spoofing accurately. Say the number appeared on caller ID. Don't claim the number's owner definitely made the call. Spoofed numbers often belong to unrelated people or businesses.

If your own number is being spoofed or is repeatedly labeled as spam, the FCC complaint page has a separate issue for that problem.

Choosing the right level of protection

Match the setting to the calls you actually need.

If you almost never hear from new people, silence unknown callers and let contacts through. If businesses, schools, or service providers call you, use caller labeling and voicemail screening instead of blocking every unknown number. If the volume of nuisance calls is high, combine phone controls, carrier filtering, and a reputable blocking app. On a home phone, ask the provider about call screening before you buy a separate device. On a shared line, keep the filter adjustable so one person's important call isn't blocked for everyone.

Give the new settings a week. Add legitimate callers that got filtered. Tighten the filter only if the unwanted calls keep coming.

Frequently asked questions

Does the Do Not Call Registry stop robocalls? No. It can reduce some legitimate sales calls. Scammers and many exempt callers may keep dialing. Call blocking and reporting are separate steps.

Is a call labeled "Spam" definitely fraudulent? No. A label is a warning based on information from the phone, carrier, or app. Let the call go to voicemail and verify the caller yourself.

Is a local-looking number safe to answer? No. Caller ID can be spoofed. A local number is not proof that the caller is local or trustworthy.

Should I call back an unknown number? Only after you have a reason to believe the call is legitimate. Check the voicemail, then contact the claimed organization through a number you found independently.

Can the FCC trace a spam call for me? The FCC complaint system isn't a personal tracing or refund service. Submit the details anyway, especially if the call involved spoofing, impersonation, or repeated illegal telemarketing.

Turn on unknown-caller screening on your phone now, register the number at donotcall.gov, and save ReportFraud.ftc.gov and the FCC unwanted-calls complaint page so those links are ready if a suspicious call still gets through.