iOS 13 has a new feature that might just save you from all spam and robocalls. The new Silence Unknown Callers feature will mute all calls coming from a number that’s not in your contact list.

Stopping the Endless Stream of Spam Calls

Silence Unknown Callers is a simple toggle that will automatically block unknown numbers from calling you. Your contacts and people you’ve interacted with will still be able to call you, but you won’t be bothered by incoming calls from anyone else.

This feature is one of the biggest reasons we’re excited for iOS 13 when Apple releases it sometime in fall 2019.

How Silence Unknown Callers Works

The Silence Unknown Callers feature is quite a blunt instrument—it’s a simple toggle in Settings. Once enabled, any call you receive from an unknown number will be silenced. If Siri Intelligence finds the number in the Mail, Messages, or Contacts app, the call will come through.

You can think of it as iOS automatically hitting the Decline button for you. You’ll still get a Missed Call notification, and you’ll find the number in the Recents list in the Phone app.

If you have voicemail enabled, the call will automatically go to the voicemail. This is where the visual voicemail feature will come in handy (availability and charges depend on your carrier).

When you go to the “Voicemail” tab in the Phone app, you’ll be able to listen or read the transcript of the voicemail (as you can see in the screenshot below).

If the message is important, you can choose to call them back. If not, delete the voicemail, and if needed, block the number.

In our testing, we found that if you call the number back, any subsequent calls you get from the number won’t be silenced automatically.

RELATED: How to Make iOS 10 Transcribe Your Voicemails Into Text

How to Enable Silence Unknown Callers

This feature isn’t enabled by default. To enable it after upgrading to iOS 13, open the Settings app and go to the “Phone” section.

Scroll to the bottom of the page and tap on the toggle next to “Silence Unknown Callers” to enable the feature.

How to Ensure You Won’t Miss Important Calls

What Silence Known Callers feature lacks is nuance and control. If you want to be sure you’ll get incoming calls from someone, add the person’s phone number to your contacts. That’s all you can do to control it.

Unlike the Do Not Disturb feature, a call won’t come through after repeated attempts. With this feature enabled, your iPhone won’t ring even if someone calls you six times in a row.

If you’re concerned you might miss an important or emergency call coming from a payphone or a hospital, then you should not enable this feature.

However, you will still get voicemails from unknown callers. As long as you’re checking your voicemails, you won’t miss anything important.

How to Check Voicemail for Missed Calls

Some of those unknown calls may be important, and hopefully, those important callers will leave a voicemail for you. You can check voicemails from your missed calls from the Phone app.

If you have voicemail enabled, open the Phone app and go to the “Voicemail” tab. If you haven’t enabled it yet, you can do it from this screen.

You’ll see voicemails from callers at the top. Tap on a voicemail from the list or select the corresponding “i” button to expand the voicemail.

Tap on the “Play” button to listen to the message. If you have the Visual Voicemail feature enabled, you’ll see a snippet of the transcribed text below the number. Tap on the box to expand the text.

Alternatives to Silence Unknown Callers

If silently blocking most phone numbers in the world sounds too aggressive to you, you have some alternatives that can silence spam calls.

While it’s not the exact same thing, you can set up the Do Not Disturb (DND) feature only to allow calls from Favorites. DND also has an option to allow repeated calls. This means that a second call from the same number within three minutes won’t be silenced.

You can also use a spam blocker app like Hiya to automatically block spam and robocalls, but it’s not a complete fix. The success rate of the app will depend on its database of spam callers, which is never fully complete. While it might not block all spam calls, it should get most of them.

RELATED: Here's Why iOS 13 Makes Me Want an iPhone