Register with the National Do Not Call Registry

The National Do Not Call Registry is a free list maintained by the Federal Trade Commission (FTC) that tells telemarketers they cannot call your number. You can add your phone number at donotcall.gov or by calling 1-888-382-1222 from the phone you want to register.

Registration is permanent — your number stays on the list even if you change phone companies or move. The registry covers most telemarketing calls, but not all: political organizations, charities, surveys, and companies you have done business with in the past 18 months can still call you legally.

After you register, keep a record of the date. If a telemarketer calls after 31 days have passed, you have evidence they broke the law. The FTC does not investigate individual complaints, but patterns of violations from the same company can trigger enforcement action.

Key Takeaways

  • Register your phone number at donotcall.gov or 1-888-382-1222 to tell most telemarketers they cannot call you legally.
  • Your phone company or a third-party app can block calls automatically, and most phones have a built-in "silence unknown callers" feature that works without extra software.
  • Scammers ignore the Do Not Call Registry entirely, so blocking and filtering are more effective than registration alone for reducing unwanted calls.
  • If you answer a call and hear silence or a recorded message, hang up when ready — do not press any number or say anything, because that confirms your number is active.
  • Robocalls are illegal without your written consent, and you can report them to the FTC at donotcall.gov or to your state's attorney general.

Use Your Phone's Built-In Call Blocking Features

Every modern smartphone has a native way to silence calls from unknown numbers without blocking them entirely. On iPhone, go to Settings > Phone > Silence Unknown Callers to send calls from numbers not in your contacts to voicemail. On Android, the equivalent is Settings > Apps & Notifications > Notifications > Advanced > Caller ID and Spam Protection, then toggle on "Filter Unknown."

These features do not block the calls — they still ring through to voicemail — but they prevent your phone from interrupting you. Legitimate callers who leave a voicemail will still reach you, and you can call them back if you recognize the number.

If you want to block specific numbers permanently, both iPhone and Android let you add numbers to a block list. On iPhone, open the recent call, tap the info icon, and select "Block this Caller." On Android, open the call log, long-press the number, and tap "Block." Blocked callers cannot reach you by phone or text, and their calls go straight to voicemail.

Add a Third-Party Call Filtering App

Apps like Nomorobo, RoboKiller, and Truecaller use databases of known telemarketer and scam numbers to block calls before they reach you. Many are free or cost a few dollars per month. Nomorobo works on both landlines and cell phones; RoboKiller and Truecaller work on smartphones only.

These apps work differently than your phone's native blocking. Instead of silencing unknown numbers, they identify specific numbers as spam or scam based on reports from millions of users and known telemarketer databases. If a number matches, the app blocks it outright. Some apps also let you set rules — for example, "block all calls from numbers that have never called me before" or "allow calls only from my contacts."

The trade-off is that third-party apps see your incoming calls to work. Read the privacy policy before installing one. Most reputable apps (Nomorobo, RoboKiller, Truecaller) are transparent about what data they collect and do not sell your call history to advertisers, but the permission exists.

Ask Your Phone Company to Block Calls

Most major carriers offer call-blocking services as part of your plan or for a small monthly fee. Verizon offers Call Filter (free basic version, paid version with more features); AT&T offers Call Protect; T-Mobile offers Scam Shield. These services block known spam and robocalls at the carrier level, before they reach your phone.

Carrier-level blocking is often more effective than app-based blocking because the carrier sees all calls on their network, not just the ones that reach your phone. Ask your carrier what is included in your plan and whether you need to turn it on — some services are automatic, others require you to opt in through your account or by calling customer service.

The downside is that carrier services are less customizable than apps. You usually cannot set your own rules or see detailed logs of blocked calls. But if you want a straightforward, set-it-and-forget-it solution, carrier blocking is often the easiest route.

Do Not Engage With Unknown Callers

If you do answer a call from an unknown number and hear silence, a recorded message, or a pause before someone speaks, hang up when ready. Do not press any number, do not say anything, and do not stay on the line to listen. Telemarketers and scammers use silence and pauses to confirm that a number is active and that a human answered — that confirmation makes your number more valuable and more likely to be called again.

If a caller claims to be from your bank, the IRS, or a government agency and asks for personal information, hang up. Legitimate institutions do not call you out of the blue asking for Social Security numbers, account numbers, or passwords. If you think the call might be real, hang up and call the organization directly using the number on your bill or their official website.

Never give out your phone number to websites, forms, or contests unless you trust the source. Telemarketers buy lists of active phone numbers from data brokers. The fewer places your number appears, the fewer lists it ends up on.

Report Illegal Calls to the FTC and Your State

Robocalls — automated calls that deliver a recorded message — are illegal unless you gave written consent to receive them. If you receive a robocall, you can report it to the FTC at donotcall.gov. The FTC does not investigate individual complaints, but it tracks patterns and uses reports to identify companies breaking the law at scale.

You can also report illegal telemarketing calls to your state's attorney general office. Many states have their own telemarketing laws and enforcement teams. A quick search for "[your state] attorney general telemarketing complaint" will show you where to file.

Keep a record of the date, time, and number of any illegal call. If the same number calls repeatedly after you registered with the Do Not Call Registry, that is evidence of a violation. Screenshots of your call log or a written note with the details is enough to file a report.

Understand What the Do Not Call Registry Does and Does Not Cover

The Do Not Call Registry stops most telemarketing calls, but it has legal exceptions. Charities, political organizations, surveys, and companies you have done business with in the past 18 months can call you even if you are on the registry. Debt collectors can also call regardless of the registry, though they must follow other rules under the Fair Debt Collection Practices Act.

Scammers and illegal robocallers ignore the registry entirely because they are already breaking the law. Registration protects you from legitimate telemarketers, but it does not stop fraud. That is why blocking and filtering are so important — they catch the calls that registration cannot.

If you receive calls from a charity or political organization and want them to stop, ask them directly to put your number on their internal do-not-call list. They are required to honor that request, though it may take a few days to process.

Frequently Asked Questions

How long does it take for the Do Not Call Registry to work?

Telemarketers have 31 days from the date you register to stop calling. If a company calls within that window, they are not breaking the law yet. After 31 days, any telemarketing call is a violation. Keep your registration date so you can report violations with proof.

Can I block calls on a landline?

Landlines do not have the same built-in blocking as smartphones, but your phone company can add call-blocking features to your account. Ask your provider what options they offer. Nomorobo also works on landlines and can be added through your phone company or directly through their website.

What should I do if a scammer spoofs a number that looks like mine?

Spoofing — when a caller makes their number appear as yours or a local number — is illegal. Do not call the number back, because it is not real. Report it to the FTC at donotcall.gov. If the spoofed number is yours and you are getting calls from people who think you called them, ask your phone company if they can help trace the source.

Will registering with the Do Not Call Registry cost me anything?

No. Registration at donotcall.gov and the phone line 1-888-382-1222 are both free. Be cautious of websites that charge a fee to register you — they are scams. The only official registry is donotcall.gov.

Can I remove my number from the Do Not Call Registry if I change my mind?

Yes. You can remove your number at donotcall.gov or by calling 1-888-382-1222. Removal takes effect when ready, though it may take a few weeks for all telemarketers to update their lists.