To stop unwanted calls, enable your phone’s built-in spam blocking and register your number on the National Do Not Call list. Over 60% of unwanted calls can be blocked automatically by carrier-level filters. Set your phone to silence unknown callers.
Ready to Compare Plans?
See current pricing from every major carrier and budget brand — sorted by true total cost.
Compare Plans →Free to compare · No credit check to browse · Affiliate-supportedEnable Built-In Blocking on Your Phone
To stop unwanted calls, enable your phone’s built-in spam blocking and register your number on the National Do Not Call list. Over 60% of unwanted calls can be blocked automatically by carrier-level filters. Set your phone to silence unknown callers.
Every modern smartphone includes a native spam-blocking feature. On most devices, go to your Phone app settings and toggle “Filter Unknown Senders” or “Block Unknown Callers.” This sends calls from numbers not in your contacts directly to voicemail. According to the FCC, this single step can reduce unwanted call volume by 50% or more. Combined with a carrier filter, you can block the vast majority of nuisance calls without extra apps.
For a more aggressive approach, enable “Silence Unknown Callers” (mobile operating systems) or “Caller ID & Spam Protection” (mobile operating systems). These settings also identify potential spam in your recent calls log so you can report them.
Use Carrier Spam Filters
All major national carriers now offer free, automatic spam-blocking services built into their networks. These filters use the STIR/SHAKEN protocol to validate caller IDs and flag suspicious calls. The FCC reports that STIR/SHAKEN adoption has cut robocall volume by 40% since 2022.
To activate, log into your account online or call customer support to enable “Call Guard,” “Spam Shield,” or “Call Filter” (names vary by carrier). These services block known spam numbers and warn you of potential fraud. They are included with most plans at no extra cost. Some premium tiers offer reverse number lookup and custom block lists for a small monthly fee.
| Carrier Filter Feature | Typical Effectiveness | Cost |
|---|---|---|
| Basic spam flagging | 60-70% | Free |
| Automatic robocall blocking | 70-80% | Free |
| Custom block lists | 80-90% | Usually free or under $5/month |
Register for the National Do Not Call List
The National Do Not Call Registry, managed by the FTC, is a free tool that stops most legitimate telemarketers from calling you. As of 2025, over 255 million numbers are registered. Telemarketers must scrub their lists against this registry every 31 days. Violations can result in fines up to $50,120 per call.
To register, call 1-888-382-1222 from the phone you want to protect, or visit donotcall.gov. Your number stays on the list permanently unless you remove it. Note that the registry does not block political calls, charities, or debt collectors, but it significantly reduces commercial sales calls.
Silence Unknown Callers
Silencing unknown callers is the most aggressive built-in protection. On mobile operating systems, enable “Silence Unknown Callers” under Phone settings. On mobile operating systems, use “Block Unknown Callers” or “Caller ID & Spam Protection.” This sends any call from a number not in your contacts or recent outgoing calls straight to voicemail. Legitimate callers can leave a message, and you can call them back if needed.
This feature is especially useful for seniors or anyone receiving high volumes of spoofed calls. According to a 2025 survey by the FCC, users who enabled this setting reported a 90% reduction in unwanted calls. It works alongside carrier filters and does not interfere with emergency services or calls from saved contacts.
Report and Block Persistent Spam
For spam calls that slip through, report them to the FCC and FTC. File a complaint at fcc.gov/complaints or call 1-888-CALL-FCC. The FCC uses this data to fine violators and shut down illegal robocall operations. In 2025, the FCC levied over $300 million in fines against robocallers.
Also block the number directly on your phone: open your recent calls, tap the number, and select “Block this Caller.” For persistent spoofed numbers (where the caller ID is fake), add the area code or prefix to a block list in your carrier’s spam filter app. Never engage with the caller or press any number, which confirms your line is active.
- Block the number immediately after the call ends.
- Report to the FTC at donotcall.gov or call 1-888-382-1222.
- Enable “Scam ID” or “Scam Block” in your carrier’s account settings.
- Consider a third-party call-blocking app (e.g., Nomorobo, YouMail) for extra protection.