The four layers
| Layer | What it does | Cost |
|---|---|---|
| Carrier spam filter | Labels or blocks calls the network identifies as likely spam | Basic tier usually free; extras may cost |
| Phone settings | Silences or screens callers who aren't in your contacts | Free |
| Do Not Call Registry | Makes it illegal for most legitimate telemarketers to call you | Free |
| Manual blocking and reporting | Blocks repeat numbers and feeds data to regulators | Free |
1. Turn on your carrier's filter
The major US mobile carriers each offer a free spam-call filter, usually as an app or an account setting. It can label suspected spam on your screen and, if you choose, send high-risk calls straight to voicemail. Paid tiers may add features such as caller name display. Look in your carrier's app or website under spam, call protection or call filter. Many landline and home phone providers offer similar blocking, sometimes including a free robocall screening service.
2. Use your phone's settings
iPhone
iOS includes an option to silence unknown callers, which sends calls from numbers not in your contacts, recent outgoing calls or Siri suggestions straight to voicemail. Newer versions also offer call screening, which asks unknown callers for their name and reason before your phone rings. You'll find these in the Phone section of Settings; the exact menu path changes between iOS versions.
Android
Many Android phones have spam filtering in the Phone app's settings, often under a heading like "Caller ID and spam". Some models can screen calls automatically or ask unknown callers to state their business. Menu names differ between manufacturers, so search your settings for "spam" or "block".
Silencing unknown callers can hide calls you want, such as a doctor's office or a delivery driver. Check voicemail regularly, or save important numbers to your contacts in advance.
3. Register with the Do Not Call Registry
The National Do Not Call Registry is run by the Federal Trade Commission. Registration is free at donotcall.gov, it covers mobile and landline numbers, and it doesn't expire. Telemarketers have up to 31 days after you register to stop calling.
The registry doesn't cover every call. These are still allowed:
- Political calls, charities, surveys and debt collectors
- Companies you've done business with recently, unless you ask them to stop
- Companies you've given written permission to call you
Most importantly, criminals ignore the registry. If you're on it and still receive sales robocalls, the caller is breaking the law, which is a strong signal it's a scam. Report the call on the same site.
4. Block and report
- Block repeat numbers from your recent calls list. It's quick, though scammers often switch numbers.
- Forward spam text messages to 7726 (the digits spell SPAM). Most US carriers use this short code to collect reports.
- Report illegal robocalls and sales calls at donotcall.gov and scams at reportfraud.ftc.gov.
Habits that reduce calls
- Don't press buttons on robocalls. "Press 1 to be removed" usually confirms your number is live.
- Don't say "yes" to open questions. Answer "Can you hear me?" with a hang-up, not a yes.
- Don't call back one-ring numbers. See one-ring scams.
- Limit where you share your number. Use a second number for sign-ups, and opt out of people-search listings.