The three ways to block calls on a landline

You can block unwanted calls on a landline through your phone company's service, through a device you plug into your phone line, or through a separate answering machine or call-screening box. Which one works best depends on how many numbers you want to block, whether you want to hear who is calling before you pick up, and what your phone company offers.

Most landline providers now offer call-blocking features built into your account — sometimes free, sometimes for a small monthly fee. If your provider does not offer this, or if you want more control, a physical device that sits between your phone and the wall jack can block calls before they ring your phone. A third option is an answering machine or dedicated call-screening device that lets you hear callers before you decide whether to answer.

Key Takeaways

  • Your phone company can block calls at the network level, which stops them before they reach your phone — ask your provider what call-blocking tools they offer and whether there is a cost.
  • A call-blocking device plugged into your phone jack works without involving your phone company and can block hundreds of numbers, but requires you to manage a list yourself.
  • An answering machine or call-screening box lets you hear who is calling before your phone rings, giving you time to decide whether to answer.
  • Phone company blocking is fastest to set up but may not block spoofed numbers; device-based blocking is more reliable for spam but requires manual updates.

Call blocking through your phone company

Most landline providers — including Verizon, AT&T, CenturyLink, and regional carriers — now offer call-blocking services. The service works at the phone company's network, which means calls are blocked before they reach your phone and never ring at all. You typically manage your blocked list through your online account or by calling customer service.

Some providers offer basic call blocking free, while others charge between $3 and $5 per month. Verizon's Call Filter is free for basic blocking and $2.99 per month for advanced features. AT&T Call Protect is free for basic service. CenturyLink's Call Filter is $3.99 per month. Ask your provider what they offer — the name and cost vary by company and region.

The main limitation is that call-blocking at the network level cannot always stop spoofed calls, where a caller disguises their real number to look like a local number or a business you know. If you are getting calls from numbers that appear to be from your own area code or from a company you recognize, network-level blocking may not catch them.

Call-blocking devices you plug into your phone jack

A call-blocking device sits between your phone jack and your phone (or answering machine). When a call comes in, the device checks the incoming number against a list you create or that comes pre-loaded. If the number matches, the device blocks the call and it never rings your phone. Common devices include the CPF32 Call Blocker, the Sentry Call Blocker, and the Nomorobo device.

These devices work independently of your phone company, so you do not need to contact your provider or pay a monthly fee. Most let you block between 100 and 1,500 numbers depending on the model. You add numbers to the block list by pressing buttons on the device, through a small screen, or through a companion app on your phone.

The trade-off is that you have to manage the list yourself. When you get a call from a new unwanted number, you have to manually add it to the device. Some devices come with a pre-loaded list of known spam numbers, but that list does not update automatically — you have to read updates manually or the device updates only when you plug it in to a computer.

Answering machines and call-screening boxes

An answering machine or dedicated call-screening device lets you hear who is calling before your phone rings. When a call comes in, the device announces the caller's number out loud (if available) or displays it on a small screen. You can then decide whether to pick up or let it go to voicemail.

This approach does not block calls — your phone still rings — but it gives you control over which calls you answer. It is useful if you want to screen calls rather than eliminate them entirely, or if you want to hear the message a caller leaves before deciding whether to call back.

Some newer answering machines and call-screening devices also have a built-in block list, so you can set them to send certain numbers straight to voicemail without ringing your phone at all. Check the product description to see whether the device you are considering has this feature.

How to set up call blocking with your phone company

Call your landline provider's customer service number — it is on your bill or their website. Tell them you want to set up call blocking. They will either walk you through adding numbers to a block list over the phone, or they will direct you to log into your online account and add numbers there.

To block a number, you will need the phone number itself. Some providers let you block entire area codes or number ranges, which is useful if you are getting calls from a particular region. Others let you block numbers that match a pattern — for example, all calls from numbers that start with a certain prefix.

After you add a number to your block list, it usually takes effect within a few minutes to a few hours. If you keep getting calls from the same number, contact your provider again — they can check whether the number is actually blocked or whether the caller is using a different number each time.

Combining methods for better results

Many people use more than one blocking method at the same time. For example, you might use your phone company's free basic blocking for the worst offenders, add a call-blocking device for numbers your provider cannot catch, and keep an answering machine running so you can screen calls that get through.

If you use both a phone company block and a device block, make sure they are not set to block the same numbers — this wastes the device's memory. Instead, use your phone company's service for the numbers it handles well (like known spam databases), and use the device for numbers that are spoofed or that your provider's service is missing.

If you have an answering machine, you can also set it to answer calls after one ring, which gives you time to see the caller ID before the phone rings. This is useful for screening calls without blocking them entirely.

What to do if calls keep getting through

If you are still getting unwanted calls after setting up blocking, the caller is likely using a different number each time or spoofing a number. Spoofed calls are harder to block because the number changes or looks legitimate.

If the calls are from a business or debt collector, you have legal options. You can send a written request to stop calling, and in many cases they are required to honor it. If calls are harassing or threatening, you can file a complaint with the Federal Trade Commission at reportfraud.ftc.gov or contact your local police.

If you are getting calls from a specific company repeatedly, ask your phone company whether they can block that company's entire number range or whether they have a known spam list that includes that caller. Some providers update their spam databases regularly and may already have that number flagged.

Frequently Asked Questions

Can I block calls from a specific area code?

Some phone companies let you block entire area codes, but this is risky because you might block legitimate calls from that region. Most providers recommend blocking individual numbers instead. If you are getting many calls from one area code, ask your provider whether they can block a number range or pattern rather than the entire code.

Will blocking a number stop text messages from that number too?

Call blocking usually stops only voice calls, not text messages. If you are getting unwanted texts, you may need to block the number through your phone's built-in text-blocking feature or through your phone company's separate text-blocking service. Check with your provider about whether they offer text blocking.

What if I block a number by mistake?

You can unblock a number at any time by contacting your phone company or by removing it from your device's block list. If you used your phone company's service, log into your account or call customer service and ask them to remove the number. If you used a device, follow the device's instructions to delete the number from the list.

Do call-blocking devices work with cordless phones?

Yes, a call-blocking device plugged into your phone jack will block calls for any phone connected to that jack, including cordless phones. The device sits between the wall and your phone line, so it blocks calls before they reach any phone in your home.

Is there a cost to block calls through my phone company?

Many providers offer basic call blocking free, but advanced features may cost $2 to $5 per month. Call your provider to ask what they offer at no charge and what costs extra. A call-blocking device has no monthly fee but costs between $30 and $100 to buy.