Block telemarketers with the National Do Not Call Registry, your phone carrier's tools, or third-party blocking apps — each stops different types of calls
The fastest way to reduce telemarketer calls is to register your number with the National Do Not Call Registry, a free list maintained by the Federal Trade Commission. Telemarketers are legally required to stop calling numbers on this list within 31 days, though some still ignore it. Your phone carrier — whether that's Verizon, AT&T, T-Mobile, or another provider — also offers built-in blocking tools at no extra cost. If those two steps don't stop the calls, third-party apps like Nomorobo, RoboKiller, or your phone's native call-filtering feature can block numbers automatically before they reach you.
The reason you need more than one method is that different calls come from different sources. Legitimate telemarketers respect the Do Not Call Registry. Robocalls and scams often ignore it entirely. Your carrier's tools catch some robocalls through their own databases. Third-party apps catch others by recognizing patterns or letting users report numbers. Using all three together stops the most calls.
Key Takeaways
- Register your phone number with the National Do Not Call Registry at donotcall.gov or by calling 1-888-382-1222 — it takes two minutes and is permanent unless you remove it.
- Ask your phone carrier to turn on its free call-blocking or call-filtering service, which has a different name for each provider but stops many robocalls automatically.
- If calls continue after those two steps, download a third-party blocking app like Nomorobo or RoboKiller, or turn on your phone's built-in call filter if it has one.
- Legitimate telemarketers must stop calling within 31 days of the Do Not Call Registry registration, but scammers and robocallers often ignore it — that's why you need the other methods too.
- Never call a number back from an unknown caller claiming to be a telemarketer, and never give personal information to unsolicited callers, even if they say they're from your bank or the government.
Register with the National Do Not Call Registry
The National Do Not Call Registry is a free, permanent list that tells telemarketers they cannot call you. You can register online at donotcall.gov or by calling 1-888-382-1222 from the phone you want to register. The website takes about 30 seconds; the phone call takes about two minutes. You can register both a landline and a cell phone with the same account.
After you register, telemarketers have 31 days to remove your number from their calling lists. Some do this immediately; others take the full month. You will still receive calls from charities, political organizations, surveys, and debt collectors — the registry does not cover those. You also will not stop scammers or robocalls, because those callers ignore the law. But legitimate telemarketing calls (credit card offers, insurance quotes, home improvement companies) should drop significantly within a month.
Your registration lasts forever unless you remove it. You do not need to re-register every year, and you do not need to pay anything. If you change your phone number, you will need to register the new number separately.
Enable your phone carrier's call-blocking service
Every major phone carrier offers a free or low-cost tool to block robocalls and spam. These tools work differently depending on your carrier, but they all filter calls before they reach you. Call your carrier's customer service number (on your bill or their website) and ask them to turn on their spam-blocking feature. Here is what to ask for with each carrier:
| Carrier | Service Name | Cost |
|---|---|---|
| Verizon | Call Filter | Free basic version; $3.99/month for premium |
| AT&T | Call Protect | Free basic version; $4.99/month for premium |
| T-Mobile | Scam Shield | Free basic version; $4.99/month for premium |
| US Cellular | Call Screening | Free basic version; $4.99/month for premium |
The free versions of these services block many robocalls automatically. The paid versions add extra features like caller name lookup and the ability to block calls from specific numbers. For most people, the free version is enough. Ask the carrier to enable it on your account, and they will send you instructions to download the app or turn it on in your phone's settings.
Use a third-party blocking app if calls continue
If you still receive telemarketer and robocalls after registering with Do Not Call and enabling your carrier's tool, a third-party app can catch what the others miss. Nomorobo and RoboKiller are the most popular options. Both work by comparing incoming calls against databases of known spam numbers and by learning from user reports. When a call matches a known spam pattern, the app blocks it before your phone rings.
Nomorobo is free for cell phones and works on both iPhone and Android. You download the app, give it permission to filter calls, and it runs in the background. RoboKiller costs $3.99 per month but includes extra features like the ability to send spam callers to a fake voicemail that wastes their time. Both apps let you whitelist numbers (tell the app not to block them) so important calls still get through.
If you do not want to download an app, your phone's built-in call filter may be enough. iPhones have a "Filter Unknown Senders" option in Settings > Phone > Silence Unknown Callers. Android phones have a similar feature called "Filter Unknown" or "Spam Protection" depending on your phone model. These built-in filters are less aggressive than third-party apps but require no download and no subscription.
What to do if a telemarketer calls anyway
If a telemarketer calls after you have registered with Do Not Call, you can file a complaint with the Federal Trade Commission at reportfraud.ftc.gov. The FTC does not call you back or investigate individual complaints, but it uses the reports to identify companies that break the law repeatedly. Complaints are free and take about five minutes to file online.
Do not call the number back, even if the caller left a voicemail asking you to. Calling back confirms your number is active and can lead to more calls. Do not press buttons or say anything to an automated voice asking if you want to be removed from the list — that also confirms your number is active. Simply hang up or let your blocking app handle it.
If the call is from a scammer pretending to be from your bank, the IRS, or a government agency, hang up immediately and call the real organization directly using the number on your bill or their official website. Never give personal information, passwords, or payment details to an unsolicited caller, no matter what they claim.
Understand which calls the Do Not Call Registry does not cover
The National Do Not Call Registry stops telemarketing calls, but several types of calls are legal even if your number is registered. Charities, political organizations, and surveys can still call you. Debt collectors can call if you owe them money. Companies you have done business with in the past 18 months can call. And if you have given a company written permission to call you, they can ignore the registry.
If you want to stop calls from a specific charity or organization, ask them directly to remove your number. If they call again after you ask, you can file a complaint with the FTC. For debt collectors, you can send a written request to stop calling, though they may still contact you about a lawsuit or settlement.
Frequently Asked Questions
How long does it take for the Do Not Call Registry to work?
Telemarketers have 31 days to remove your number after you register. Some stop calling within a few days; others take the full month. Scammers and robocalls ignore the registry entirely, so you will still need your carrier's tools or a third-party app to stop those.
Do I have to pay to register with Do Not Call?
No. Registration is completely free at donotcall.gov or by calling 1-888-382-1222. You do not pay anything, and you do not need to re-register. Be cautious of websites that charge money to register you — those are scams.
Will blocking calls stop my bank or doctor from reaching me?
Legitimate businesses like banks and doctors usually call from numbers you recognize or have called before. If you are worried about missing important calls, whitelist those numbers in your blocking app or carrier tool so they always get through. You can also ask your doctor or bank to text you instead of calling.
What if I want to receive calls from telemarketers again?
You can remove your number from the Do Not Call Registry at donotcall.gov or by calling 1-888-382-1222. You can also turn off call-blocking in your carrier's app or phone settings. The change takes effect immediately.
Can I block a specific number permanently?
Yes. On iPhone, open the Phone app, find the number in your call history, tap the info icon, and select "Block this Caller." On Android, open the Phone app, find the number, tap the three dots, and select "Block number." That number will never call you again. You can also add numbers to your carrier's or blocking app's blacklist.