Spam calls have one thing in common: they almost always come from a number you have never saved. Both iPhone and Android now let you decide what happens to those calls before your phone ever rings — silence them, screen them, or let them through. The trick is picking the setting that blocks the robocalls without accidentally silencing your delivery driver, your doctor's office, or a job interviewer.
What counts as an "unknown caller"?
On both platforms, an unknown caller is simply a number that is **not saved in your contacts**. A robocall from a spoofed number and a first-time call from a hospital switchboard look identical to the setting, which is why the "silence everything" option is not always the right choice.
There are three levels of protection: **Identify** (show a "Suspected spam" label but still ring), **Screen** (answer automatically, ask who is calling and why, show you a live transcript), and **Silence** (never ring; send the call to voicemail). Start with screening if you expect calls from new numbers; move to silence only if the spam volume makes screening feel like a chore.
Silence or screen unknown callers on iPhone
On current iPhones, Apple groups these controls under **Screen Unknown Callers**. The menu moved in newer iOS versions, so follow the path that matches your phone.
1. Open **Settings**, then tap **Apps**.
2. Tap **Phone**.
3. Scroll to **Screen Unknown Callers**.
4. Choose one option:
- **Never** — unknown calls ring like any other call.
- **Ask Reason for Calling** — your iPhone answers first, asks the caller to say who they are and why they are calling, then rings you with their answer on screen so you can decide.
- **Silence** — calls from unsaved numbers are silenced and sent to voicemail. They still appear in your Recents list, so you can call back.
The same menu exists under **Settings → Apps → FaceTime**, where it is a simple **Silence Unknown Callers** switch for FaceTime calls from unknown numbers.
Older iOS: the original Silence Unknown Callers switch
On older iOS there is no three-way choice. Go to **Settings → Phone** and toggle **Silence Unknown Callers** on or off. On means unsaved numbers go to voicemail without ringing; off means every call rings.
Filter unknown and spam calls into their own lists
Silencing is only half the story — you also want the missed calls somewhere tidy instead of mixed into your normal history:
- Go to **Settings → Apps → Phone**.
- Scroll to **Call Filtering** and turn on **Unknown Callers**. Missed calls and voicemails from unsaved numbers move to a separate Unknown Callers list.
- If your carrier supports it, turn on **Spam** in the same section. Suspected spam calls are silenced, sent to voicemail, and filed on a Spam list.
- To review them, open the **Phone** app, tap **Filter**, then tap **Unknown Callers** or **Spam**.
Block spam calls on Android (Google Phone app)
On Pixel phones and most other Android phones that use Google's Phone app, the controls live inside the Phone app itself rather than in system Settings.
- Open the **Phone** app.
- Tap the **three-dot menu**, then **Settings**.
- Tap **Caller ID & spam** (on some phones it is called **Spam and Call Screen**).
- Turn on **See caller ID & spam**. It is on by default and shows a "Suspected spam caller" or "Spam" label on incoming calls.
- If available, turn on **Filter spam calls**. Suspected spam calls will not ring; they stay in your call history and can still leave voicemail.
Use Call Screen on Pixel
Call Screen is Google's strongest option. It answers the call for you, asks who is calling and why, and shows you a live transcript while the caller talks.
- Open the **Phone** app → **three-dot menu** → **Settings** → **Spam and Call Screen** → **Call Screen**.
- Choose a protection level: **Basic** (decline known spam only), **Medium** (screen suspicious numbers), or **Maximum** (screen all unknown numbers).
- For any incoming call, you can also tap **Screen call** manually instead of answering.
Availability is the catch: automatic screening works on Pixel phones in the US, UK, Canada, Australia, and Ireland, while manual screening works in more countries, including France, Germany, India, Italy, Japan, and Spain. Automatic screening does not run while roaming, and Google advises against it if you use call forwarding.
Block spam calls on Samsung Galaxy
Samsung uses its own Phone app with **Smart Call** (powered by Hiya in the US) for caller identification.
1. Open the **Phone** app and tap the **three-dot menu** → **Settings**.
2. Tap **Caller ID and spam protection** and turn it on (accept the terms if prompted).
3. Turn on **Block spam and scam calls**, then choose a level:
- **Only block high-risk scam calls** — the safer starting point; lower-risk spam still rings with a warning.
- **Block all spam and scam calls** — the strict option; blocked calls are logged so you can check nothing important was caught.
If your carrier or country does not offer Caller ID and spam protection, use the fallback in the same Settings menu: **Block numbers** → **Block unknown/private numbers**. This blocks *every* unsaved number, not just suspected spam — only use it if you genuinely never expect calls from new numbers.
Before you turn anything on: save the numbers that matter
This is the step people skip, and it is the one that causes missed appointments. Before enabling silence or strict blocking, add these to your contacts: your doctor, pharmacy, and clinic numbers; your child's school or daycare office; your bank's official callback number (look it up on the bank's own site); delivery companies you use; and any employer, repair service, or landlord you are waiting to hear from.
If a call you expected was silenced anyway, check the Unknown Callers / Spam list or your Recents, save the number, and call back. On iPhone you can also mark a filtered number as known; on Android, use the "Not spam" option if a legitimate call was mislabeled.
Troubleshooting: when the setting does not seem to work
- **"Spam calls still ring."** You only turned on identification, not filtering. On iPhone, choose **Silence**; on Android, turn on **Filter spam calls** or a Call Screen protection level; on Samsung, enable **Block spam and scam calls**.
- **"An important call went to voicemail."** The number was not in your contacts. Save it and call back. If you are expecting calls from new numbers this week, switch from Silence to **Ask Reason for Calling** (iPhone) or **Medium** protection (Pixel) until the week is over.
- **"I see no Call Screen option."** Call Screen is Pixel-only for automatic screening and is not available in every country. Use **Filter spam calls** instead, which works on far more phones.
- **"Samsung shows no Caller ID and spam protection."** It is not offered in every country or by every carrier. Use **Block numbers** instead, or check whether your carrier offers its own spam-filtering app.
- **"Voicemail is full of spam."** Silenced calls can still leave voicemail. Consider screening instead of silence, so robocallers hang up before reaching voicemail.
Frequently asked questions
**Will silencing unknown callers block texts too?**
No. These settings only affect voice calls. Spam texts are handled separately by your messaging app's spam protection.
**Do silenced calls show up anywhere?**
Yes. On iPhone they appear in Recents and in the Unknown Callers or Spam list. On Android they stay in call history and can still leave voicemail.
**Will this stop all spam calls?**
No — no built-in setting catches everything. Spammers constantly rotate numbers. For numbers that keep getting through, block and report them individually from Recents.
**Does silencing unknown callers affect emergency calls?**
No. Outgoing emergency calls always work, and on iPhone, calling emergency services turns screening off for 24 hours so responders can call you back.
Limitations to know before you start
- Screening and filtering only apply to **unsaved numbers**. A scammer who spoofs a saved contact's number can still get through.
- Availability varies by phone model, software version, carrier, and country. Call Screen is the most restricted; basic caller ID and spam filtering are the most widely available.
- Silenced calls can still leave voicemail, so check your filtered lists regularly.
- Menu wording shifts between software versions. If a label here differs slightly on your phone, look for the closest match — the setting is in the same place.
- These steps were verified against official Apple and Google support documentation; nothing here requires a paid app or a subscription.
Pair call filtering with other sound controls to make your phone quieter on your terms: give important people their own per-contact ringtone on iPhone, set a different notification sound for WhatsApp, or create custom vibration patterns so you know who is calling by feel alone.