The three ways to block calls on a landline

Most home phone providers offer call blocking built into your account, either free or for a small monthly fee. You can also use a standalone device that sits between your phone line and your handset, or program your phone itself if it has that feature. Which option works depends on your phone type, your provider, and how many numbers you want to block.

The easiest route is usually your provider's service, because it blocks calls before they ring your phone at all. Standalone devices are useful if you rent and cannot change your service, or if your provider charges for blocking. Phone-level blocking works on any line but requires you to enter each number manually into your handset.

Key Takeaways

  • Your phone company can block specific numbers or entire categories of calls (spam, international, etc.) through your account settings or a phone call to customer service.
  • Standalone call blockers like the CPF3000 or Nomorobo device plug between your wall jack and phone, and work with any provider without monthly fees.
  • Modern cordless and landline phones often have a "block number" button or menu option that stores unwanted numbers in a rejection list.
  • Some providers charge $3 to $5 per month for call blocking, while others include it free; ask your provider what they offer before buying a separate device.
  • Robocalls and spoofed numbers may not be stopped by blocking a single number, so combining your provider's service with a device often works better than either alone.

Blocking through your phone company

Call your provider's customer service line and ask what call blocking options they offer. Most major carriers—Verizon, AT&T, CenturyLink, Frontier, and others—have at least one service available. Some are free; others cost between $3 and $5 per month. Ask the representative to explain what each option blocks and whether there is a free trial.

Common provider services include Call Filter (Verizon), Call Protect (AT&T), and Nomorobo (available through many carriers). These services typically let you block specific numbers you report, block entire categories like international calls or suspected spam, or set your phone to ring only for numbers in your contacts. Some also send suspected spam calls to voicemail instead of ringing your phone.

To add a number to your block list, you usually log into your account online, call customer service, or use a code on your phone (often *60 or *77, depending on your provider). Ask your representative which method your account supports. Changes usually take effect within a few minutes.

Using a standalone call-blocking device

A standalone device plugs into the wall jack where your phone line enters, and your phone plugs into the device. It screens calls before they reach your handset and blocks numbers on a list you create. Popular models include the CPF3000 (made by Clarity), the Nomorobo device, and the ClearSounds CSC600. Most cost between $40 and $100 and have no monthly fee.

To block a number, you press a button on the device when an unwanted call comes in, or you enter numbers manually into its memory. Some devices let you upload a block list from your computer. The device stores anywhere from 50 to 500 numbers, depending on the model. When a blocked number calls, the device either silences the ring or sends the call straight to voicemail.

Standalone devices work with any phone company and any phone type, which makes them useful if you rent your home or if your provider does not offer blocking. They also work when ready—no waiting for your account to update. The trade-off is that you have to manage the block list yourself, and the device takes up space near your phone jack.

Blocking numbers directly on your phone

Many cordless phones and modern landline handsets have a built-in block feature. Check your phone's manual or look in the settings menu for an option like "Block Number," "Reject List," or "Do Not Disturb." If your phone has this feature, you can usually press a button during an unwanted call to add that number to a rejection list.

The downside is that the call still rings your phone before you can block it, so you do not get the benefit of stopping it before it reaches you. Also, your phone's memory is usually limited—most can store only 10 to 30 blocked numbers. This method works best if you have a small number of repeat callers you want to silence, rather than as your main defense against spam.

To add a number, look for a "Block" or "Reject" button on your handset, or navigate to your phone's settings menu and find the call blocking option. Some phones let you block by name as well as number, which is useful if the same person calls from multiple lines.

Dealing with spoofed and robocalls

Blocking a single number does not always work against robocalls and spam, because callers often use fake numbers that change with each call. A number that called you yesterday may never call again. Blocking that one number stops that one call but does not protect you going forward.

The best defense is to combine your provider's service with a standalone device or your phone's built-in blocking. Your provider's service can block entire categories (like all international calls or all calls from numbers that do not match a real phone company pattern), while your phone or device can block the specific repeat offenders you encounter. Together, they catch more calls than either alone.

If you are getting many robocalls, ask your provider whether they offer a "spam filter" or "robocall detection" service in addition to number blocking. These services use patterns to identify likely spam before it reaches you, rather than relying on a list of known bad numbers.

What to do before blocking a number

Before you block a number, make sure it is actually unwanted. Legitimate businesses sometimes call from numbers that look like spam, and blocking them means you might miss important calls about your account, delivery, or appointment. If you are not sure who is calling, let it go to voicemail and listen to the message first.

If a number keeps calling after you have asked them to stop, or if they are harassing you, document the calls (write down the date, time, and what was said). This record is useful if you need to report the caller to the Federal Trade Commission or to law enforcement. You can file a complaint at reportfraud.ftc.gov or call the FTC at 1-877-438-4338.

For calls that are clearly spam or robocalls, blocking is the right move. For calls from people or businesses you might want to hear from later, consider sending them to voicemail instead of blocking them completely.

Frequently Asked Questions

Can I block a number that keeps changing or spoofing a different number each time?

Blocking individual numbers will not stop a caller who uses a different number each time. Instead, ask your provider about spam filters or robocall detection services, which identify patterns rather than matching specific numbers. You can also ask your provider to block entire categories, like all calls from numbers that do not match a real phone company format.

Will blocking a number stop them from leaving voicemail?

That depends on your provider and device. Some blocking services send blocked calls straight to voicemail, so the caller can still leave a message you can listen to later. Others disconnect the call entirely. Ask your provider or check your device manual to see which behavior yours uses.

What if I block a number by mistake and want to unblock it?

Most providers let you remove numbers from your block list through your online account or by calling customer service. On a standalone device or phone, look for an "Unblock" or "Remove from Reject List" option in the settings menu. Keep a list of numbers you have blocked so you can find them if you need to unblock one later.

Do I need to pay for call blocking, or is it free?

It varies by provider. Some include basic call blocking free with your account, while others charge $3 to $5 per month for advanced features like spam detection. Standalone devices have no monthly fee but cost $40 to $100 upfront. Ask your provider what they offer before you buy a separate device.

Can I block calls on a phone line I share with other people?

Yes, but blocking through your provider affects the entire line, so everyone in your household will not receive those calls. If you want to block calls only for yourself, use a standalone device or your individual handset's blocking feature instead. That way, other people on the line can still receive calls from that number if they want to.