The fastest way to stop telemarketer calls is to register your number on the National Do Not Call Registry, then use your phone's built-in call blocking tools

The National Do Not Call Registry stops most telemarketing calls within 31 days of registration. You register once, at no cost, and it stays active for five years. After that window, telemarketers are legally required to remove your number from their calling lists — though enforcement is uneven, and some calls will still get through.

Beyond the registry, your phone itself has blocking features that work when ready. On iPhone, you can silence unknown callers entirely. On Android, you can block numbers one at a time or use a third-party app that filters calls before they ring. The combination of registry registration plus phone-level blocking stops most unwanted calls within a few days.

Key Takeaways

  • Register your phone number at donotcall.gov or by calling 1-888-382-1222 from the phone you want to protect; the registry covers both landlines and cell phones.
  • iPhone users can turn on "Silence Unknown Callers" in Settings to send unrecognized numbers straight to voicemail without ringing.
  • Android phones let you block individual numbers through the Phone app, or use a third-party filter like Google's Call Screen to screen calls before they reach you.
  • Legitimate businesses you have a relationship with — your bank, your doctor, your utility company — can still call even after registry registration.
  • If telemarketer calls continue after 31 days, report them to the Federal Trade Commission at reportfraud.ftc.gov so enforcement action can be taken against repeat violators.

Register with the National Do Not Call Registry

The National Do Not Call Registry is run by the Federal Trade Commission. When you register, you are telling telemarketing companies they cannot call you. The law gives them 31 days to remove your number from their lists, though some calls may still arrive during that window.

You can register two ways. Online, go to donotcall.gov and enter your phone number. By phone, call 1-888-382-1222 from the number you want to protect. Both methods are free. The registry covers cell phones and landlines equally. You only need to register once per number — it stays active for five years, then you can re-register if you want to.

After 31 days, most telemarketing calls should stop. However, some calls are exempt from the registry: charities, political organizations, surveys, and companies you have done business with in the past 18 months can still call. Scammers also ignore the registry, which is why blocking at the phone level matters too.

Use iPhone's built-in call silencing

If you have an iPhone, the fastest way to stop unknown numbers from ringing is to turn on "Silence Unknown Callers." This feature sends calls from numbers not in your contacts straight to voicemail without making your phone ring or vibrate.

To turn it on: open Settings, tap Phone, scroll down and tap "Silence Unknown Callers," then toggle it on. Calls from people in your contacts, your recent calls, and your voicemail will still ring normally. Everything else goes silent.

This is not the same as blocking — the calls still arrive, they just do not disturb you. If you want to block a specific number instead, open the Phone app, find the number in your recent calls, tap the info icon, and select "Block this Caller." That number cannot reach you at all.

Block calls on Android using the Phone app or a filter

Android phones let you block numbers directly through the Phone app. Open the Phone app, find the telemarketer's number in your call history, press and hold it, then tap "Block number." That caller cannot reach you again.

If you want to filter unknown callers before they ring, use Google's Call Screen feature (available on Pixel phones and some other Android models). Go to Settings, tap Apps and Notifications, then Phone app, then Call Screen. Turn it on. Call Screen will answer suspected spam calls automatically and transcribe them so you can read what they wanted without being interrupted.

For older Android phones or other brands, third-party apps like Nomorobo, RoboKiller, or Whoscall can filter calls based on known spam numbers. These apps cost between $2 and $4 per month. They work by comparing incoming calls against databases of known telemarketer numbers and blocking them before your phone rings.

Report ongoing calls to the Federal Trade Commission

If telemarketer calls continue after 31 days on the Do Not Call Registry, report them. The FTC uses these reports to identify repeat violators and take legal action.

Go to reportfraud.ftc.gov and select "Unwanted Calls" from the menu. Enter the phone number that called you, the date and time, and what they were selling. You can report multiple calls from the same number in one submission. The FTC does not contact you about individual reports, but the data goes into enforcement cases.

Keep a record of the calls yourself: write down the date, time, and what they said. If the same number calls repeatedly after you have blocked it, that is evidence of a violation. The FTC looks for patterns across many reports, so your report contributes to a larger case even if nothing happens when ready.

Understand which calls are not covered by the registry

The Do Not Call Registry does not stop all calls. Charities, political organizations, and surveys can call even after you register. So can companies you have done business with in the past 18 months — your bank, your insurance company, your utility, your doctor's office. If you do not want calls from a specific business you have a relationship with, call them directly and ask to be removed from their calling list.

Scammers and illegal telemarketing operations ignore the registry entirely. If a call is offering a prize you did not enter, claiming you owe money, or asking for personal information, it is likely a scam. Do not answer, do not call back, and block the number. Report it to the FTC at reportfraud.ftc.gov.

Why phone-level blocking matters more than the registry alone

The Do Not Call Registry is effective against legitimate telemarketing companies that follow the law. But it takes 31 days to work, and it does not stop scammers. Phone-level blocking — silencing unknown callers on iPhone or using a filter on Android — stops unwanted calls when ready, whether they are registered telemarketers or not.

The best approach is to do both: register with the Do Not Call Registry so legitimate companies stop calling, and use your phone's blocking tools so you do not hear from anyone else. After 31 days, most of your unwanted calls should be gone. Any that remain are either exempt from the registry (charities, businesses you know, surveys) or illegal (scammers). Block those numbers individually or use a filter app to handle them automatically.

Frequently Asked Questions

Do I have to pay to register with the Do Not Call Registry?

No. Registration is free whether you do it online at donotcall.gov or by phone at 1-888-382-1222. The registry is run by the Federal Trade Commission and costs nothing to use. Be cautious of websites that charge a fee to register you — they are not official and you do not need them.

Will the registry stop calls from my bank or my doctor?

No. Companies you have an existing relationship with can call you even after you register. If you do not want calls from a specific business, call them directly and ask to be removed from their calling list. They are required to honor that request within 30 days.

What should I do if someone calls claiming to be from the Do Not Call Registry?

Hang up. The FTC never calls people to confirm Do Not Call registration or to ask for personal information. If someone calls claiming to be from the registry, it is a scam. Block the number and report it to the FTC at reportfraud.ftc.gov.

Can I block calls on a landline?

Yes, you can register a landline with the Do Not Call Registry. For blocking at the phone level, ask your phone service provider — most offer call blocking features for a small monthly fee, or you can use a device like a call blocker box that plugs into your phone line. These devices screen calls before they ring your phone.

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

Telemarketing companies have 31 days to remove your number from their calling lists after you register. Most calls should stop within that window. Scammers and illegal operations may not stop at all, which is why blocking at the phone level is important too.