How to stop spam calls for good
Spam calls keep coming because your phone number is bought and sold by data brokers. Here are the free steps that actually cut them down — plus the one move that stops them at the source.
To stop spam calls: register your number free at donotcall.gov, turn on your carrier’s free call filter (AT&T ActiveArmor, Verizon Call Filter or T-Mobile Scam Shield), and switch on your phone’s built-in spam filter (iPhone’s “Silence Unknown Callers”, Android’s “Filter spam calls”). The durable fix is removing your number from the data brokers that sell it — they re-list it every few weeks, so it has to stay removed.
Free steps that cut spam calls today
Do these in order. None cost anything, and together they’ll noticeably reduce the calls you get.
Add your number for free at donotcall.gov. It stops legitimate telemarketers within about 31 days — but it won’t stop scammers and illegal robocallers, who ignore it. Treat it as a baseline, not a fix.
AT&T ActiveArmor, Verizon Call Filter and T-Mobile Scam Shield all have free tiers that label or block likely-scam calls using STIR/SHAKEN caller-ID authentication. Enable it in your carrier’s app — it catches a lot of spoofed numbers automatically.
On iPhone, enable “Silence Unknown Callers” (Settings → Apps → Phone) so only saved or recent contacts ring through. On Android, turn on “Caller ID & spam” and “Filter spam calls” in the Phone app. Filtered calls still leave voicemail.
Never press a button to “opt out” of a robocall and never call back an unknown number — both confirm your line is active and lead to more calls. Let unknown numbers go to voicemail, block the worst offenders, and report scams at reportfraud.ftc.gov.
Block spam calls on your phone (iPhone & Android)
Your phone already has spam filtering built in — here’s exactly where to switch it on.
- Settings → Apps → Phone → turn on Silence Unknown Callers — numbers not in your contacts or recent outgoing calls go straight to voicemail.
- Install your carrier’s app (ActiveArmor, Call Filter or Scam Shield) for automatic scam labeling on top of that.
- On any spam call, open the call info and tap Block this Caller; report junk texts with “Report Junk”.
- Phone app → Settings → Caller ID & spam → enable “See caller & spam ID” and “Filter spam calls”.
- On a Pixel, turn on Call Screen so Google answers and screens unknown callers before they ring you.
- Press and hold a number in Recents → Block / report spam to silence and report it.
Unknown caller, No Caller ID and “Potential Spam”: what your screen is telling you
Three different labels, three different causes. Knowing which one you are looking at decides whether it is worth answering.
The caller withheld their number on purpose, usually with *67 or a permanent setting on their line. Clinics, recruiters, collections agencies and privacy-minded individuals all do it, so this is not proof of a scam by itself. It does mean you have nothing to check afterwards, which is reason enough to let it ring out. A caller with a real reason to reach you leaves a voicemail.
Here the number never arrived at all, which happens with some international routing, internet calling and older carrier equipment. Same practical answer as above, and the same setting silences both: “Silence Unknown Callers” on iPhone, spam filtering in the Android Phone app. If you want to know who it was, search the number in quotes rather than calling it back — and skip the reverse-lookup sites that ask you to sign up, because most of them are people-search brokers that will publish a page about you next.
That label comes from your carrier’s network, not from your handset guessing. Under the STIR/SHAKEN authentication rules carriers check whether a call really originates from the number it displays, and they score behaviour like a single line dialling thousands of people an hour. A labelled call is usually exactly what the label says. Note that most carriers only silence those calls once you turn that on in their app — by default they just tag them.
For a single call, dial *67 and then the number. To withhold it on every call, turn off “Show My Caller ID” on iPhone (Settings → Apps → Phone) or set Caller ID to “Hide number” in the Android Phone app’s calling-account settings; some carriers have to switch line blocking on first. Emergency services and toll-free numbers still see your number either way, and plenty of people now route withheld calls straight to voicemail, so it is a privacy tool rather than a way to be sure of getting through.
The calls doing the rounds right now
Filters cut the volume; the ones that get through are worth recognising by script. Sheriffs across the country spent this summer warning about the jury duty scam call — a “deputy” says you missed a summons and wants a bond paid in gift cards. Every autumn brings the Medicare enrollment calls, and if the target is an older relative, the guide for elderly parents covers the conversation to have before the next one rings.
The real source: data brokers selling your number
Blocking and filtering treat the symptom. The reason the calls exist is that data brokers and people-search sites publish and sell your phone number — to lead-generation companies, marketers and, indirectly, the robocallers who buy those lists. As long as your number is listed, new callers keep discovering it.
The highest-leverage move is to remove your number from those sites. Start with our free, step-by-step data-broker opt-out guide — it covers the biggest people-search sites and exactly how to get off each one.
The catch: brokers re-scrape public records and re-list your number every few weeks to months, so a one-time opt-out fades. Keeping it removed means re-checking those sites on a schedule.
Cut spam calls off at the source
PersProtect finds where your phone number is listed across 499 broker and people-search sites, removes it, and keeps re-checking so it doesn’t creep back. Start with a free scan to see who’s listing you.
See who’s selling my number — free scan →Stopping spam calls, answered
What does “No Caller ID” mean, and who is calling?
It means the caller withheld their number, usually by dialling *67 before yours or by setting their phone to hide it. Doctors’ offices, recruiters, debt collectors and people who simply prefer privacy all do it, so a hidden number is not proof of a scam on its own. What it does tell you is that you cannot check who it was afterwards, which is why the safe response is to let it go to voicemail. Anyone with a real reason to reach you will leave one.
What is the difference between “Unknown Caller” and “No Caller ID”?
“No Caller ID” means the number was deliberately blocked. “Unknown Caller” or “Unavailable” usually means the number never arrived at all — a common result with some international routing, internet calling and older carrier equipment. Both come through as anonymous, and both get silenced by the same setting: “Silence Unknown Callers” on iPhone, or spam filtering in the Android Phone app.
Why does my phone label calls “Potential Spam” or “Scam Likely”?
That is your carrier’s network filtering, not your handset guessing. Under the STIR/SHAKEN caller-ID authentication rules, carriers check whether a call is really coming from the number it claims, and they score patterns like one line dialling thousands of people. A labelled call is very likely what the label says, and you are free to ignore it. Nothing is blocked by default, though — most carriers only silence labelled calls once you switch that on in their app.
How do I find out who called me from a number I do not recognise?
Search the number in quotes and see whether complaint sites and forums already have it; a heavily reported number tells you enough. Avoid the reverse-lookup sites that ask you to register or pay, because most of them are people-search brokers that will happily also publish a page about you. Do not call the number back to find out. Calling back confirms your line is live and, on premium-rate numbers, is the whole point of the missed call.
How do I hide my own number when I call someone?
Dial *67 before the number for a one-off withheld call; the other person sees “No Caller ID” or “Private”. To hide it permanently, turn on Settings → Apps → Phone → Show My Caller ID (off) on iPhone, or Phone app → Settings → Calling accounts → Caller ID → Hide number on Android; some carriers have to enable line blocking first. Two limits worth knowing: 911 and toll-free numbers still receive your number, and many people now send withheld calls straight to voicemail.
Does the Do Not Call Registry stop scam calls?
It stops legitimate telemarketers, not scammers — illegal robocallers already ignore the law. The registry is worth doing, but pair it with your carrier’s call filter and, most importantly, getting your number off the data-broker sites that sell it.
Why am I suddenly getting more spam calls?
Your number most likely landed on new marketing or lead-generation lists — often after filling out a form, a purchase, or a data breach. Data brokers buy, repackage and resell these lists, so once your number is circulating it spreads quickly.
Should I answer or call back unknown numbers?
No. Answering, speaking, or calling back confirms your number is active and reachable, which increases the calls you get. Let unknown numbers go to voicemail, then block and report the obvious spam.
Does blocking individual numbers actually help?
Only a little. Scammers spoof and rotate caller IDs constantly, so blocking one number rarely stops them. Carrier-level filtering (which uses caller-ID authentication) helps more — and reducing how widely your number is listed helps most of all.
How do I stop my phone number from being sold?
Opt out of the data brokers and people-search sites that publish it — see our free data-broker opt-out guide. The catch is they re-list you every few weeks, so your number needs to be removed and then monitored continuously to stay off the market.
Stop the calls — and keep them stopped
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