Block Spam Calls on iPhone and Android: Built-In Screening, Filters and Carrier Tools

By Web Asset House Studio · October 29, 2026

Note: Some future links on this site may be affiliate links. We never claim hands-on testing; guides are researched from the public sources listed in each article.

How we wrote this: A summary of Apple's "Manage unknown callers on iPhone" and "Screen and block calls on iPhone" pages, Google's Phone app help pages on caller ID and spam, blocking and Call Screen, the FTC's "How To Block Unwanted Calls" and the FCC's Call Blocking Tools and Resources (linked below), checked October 29, 2026. Menu names vary by phone model and software version.

The FTC's point is simple: scammers don't care if you're on the Do Not Call Registry, so your best defense is call blocking and call labeling. Your phone already has both built in. Here's where to find them, plus what your carrier can add.

iPhone

Apple's settings live under Settings > Apps > Phone.

Screen or silence unknown callers. Scroll to Screen Unknown Callers and pick one:

Never: calls from numbers not in your contacts ring normally.
Ask Reason for Calling: your iPhone answers unknown numbers first, asks the caller for their name and reason, then rings and shows you the answer so you can decide.
Silence: unknown numbers go straight to voicemail and appear in Recents.

Apple's notes: add important numbers (family, school, doctor) to Contacts so they always get through; calls aren't screened while you're roaming; and if you call emergency services, call screening turns off for 24 hours.

Filter unknown and spam calls. Under Call Filtering, turn on:

Unknown Callers: missed calls and voicemails from unknown numbers move to a separate Unknown Callers list. You can mark a caller as known so future calls aren't filtered.
Spam: calls your carrier identifies as potential spam or fraud are silenced, sent to voicemail and moved to a Spam list.

Caller identification. In Call Blocking & Identification, you can turn on Business Call Identification (from Apple Business Connect or your carrier) and supported caller ID apps.

Block one number. In the Phone app, tap Contacts, choose the contact, then Block Contact. Unblock under Settings > Apps > Phone > Blocked Contacts.

Android (Phone by Google app)

On phones using Google's Phone app, open the app, then More options > Settings.

Caller ID and spam. Under Caller ID and spam, "See caller ID & spam" is on by default and shows warnings like "Suspected spam caller." Google notes that to do this, numbers outside your contacts may be sent to Google to identify them. Optionally turn on Filter spam calls: you won't get notifications for them, but they stay in your call history and voicemail. On phones with automatic Call Screen, spam blocking is part of that feature instead.

Block or report a number. Tap a call in your history and choose Block / report spam. Blocked numbers are declined automatically.

Block unknown numbers. Under Settings > Blocked numbers, turn on Unknown. Google is specific about what this does: it blocks private or unidentified numbers, not numbers that simply aren't in your contacts.

Call Screen. On supported Pixel phones (automatic screening in the U.S., Canada, the U.K., Ireland and Australia), go to Settings > Spam and Call Screen (or Call Screen) and choose a protection level, or which callers to screen: spam, possibly faked numbers, first-time callers. Google says Call Screen runs on the device and doesn't use Wi-Fi or mobile data. A call it decides is spam gets hung up; otherwise your phone rings and shows what the caller said.

Your carrier and other tools

The FCC says phone companies may block calls tied to suspicious calling patterns, can automatically enroll customers in blocking services (you can opt out), and many offer blocking apps or labeling such as "spam" or "scam likely." Its Call Blocking Resources page links each major carrier's tools. The FCC suggests using both your phone's built-in tools and your carrier's.

The FTC adds that call-blocking apps are another option. Some are free and some charge a fee; some read your contacts, so check the privacy policy. And it warns that any blocking service might block some calls you want.

If your cell is also your business line

The trade-off is real for a one-person business: Silence or Unknown Callers filtering sends every new customer to voicemail. Screening (asking for a reason) is gentler. Either way, keep a clear voicemail greeting and check the filtered lists daily. See handling after-hours calls, and if your calls get flagged, why business calls get marked "Spam Likely."

Report what gets through

The FTC says to report unwanted calls at DoNotCall.gov, or at ReportFraud.ftc.gov if you lost money. For calls that ring once, see one-ring scam calls; for faked numbers, see caller ID spoofing.