Blocked and anonymous calls

How to block unwanted, restricted and spam calls

Reviewed by Sujan ThapaliyaLast updated August 22, 2026

The short answer

Blocking works in four layers: block individual numbers on the handset, silence unknown or withheld callers, enable carrier-level screening, and register on the national do-not-call list. No single layer stops everything, because most unwanted calling now presents a spoofed number that changes constantly.

There is no single setting that stops unwanted calls, and anything promising one is selling something. What exists is four layers, each catching a different share, with a cost attached to the broader ones.

What can you actually block, and what gets through?

The second row is the one people enable first and regret quietest.
Layer	Catches	Costs you
Block individual numbers	Repeat callers using one number	Nothing — but it does not scale against rotation
Silence unknown / withheld callers	Withheld calls and every unfamiliar number	New customers, clinics, recruiters, deliveries
Carrier screening and labelling	Numbers with a bad reputation score	Occasional false positives on legitimate business calls
National do-not-call registry	Compliant telemarketers	Nothing, and it takes about a minute

How do you set it up, in the right order?

1
Register on the do-not-call list
It removes the legitimate telemarketing half of the volume, and it is the only layer that reduces calls at source rather than filtering them at your handset.
2
Turn on carrier screening
Every major carrier now offers call screening or labelling, often free. It scores numbers before they reach you and is more effective than blocking numbers one at a time.
3
Block the specific repeat offenders
Long-press the entry in your call log. Worth doing for numbers that call repeatedly; pointless against rotating ones.
4
Only then consider silencing unknown callers
It is the most effective and the bluntest option. Enable it, then check voicemail daily for a week to see what it caught that you wanted.

Reporting is worth the thirty seconds

Complaints are one of the strongest inputs into the analytics that get numbers labelled and blocked network-wide. Reporting a spam call affects every other recipient, not just you — which is more than blocking it does.

The other side: keeping legitimate calls unblocked

Every layer above is a filter that a real business also has to pass. The filters do not read intent; they score patterns — call volume from one number, very short average duration, low answer rates, and complaints. A business calling customers who expect it can still be caught by all four.

What keeps calls through is identity and behaviour: numbers you own rather than pooled, a registered business name on the display, calls signed at full attestation, sensible daily volume per number, and reputation monitored per number rather than discovered when the answer rate collapses. That is what branded caller ID and number reputation management are for.

Frequently asked questions

Why do spam calls keep coming from different numbers?

Because the numbers are spoofed and rotated. Blocking one number removes exactly one number from an effectively unlimited supply, which is why number-by-number blocking never gets ahead of the problem on its own.

Does registering on the do-not-call list work?

It works on legitimate telemarketers, who are required to scrub against it. It has no effect on fraudulent callers, who were already breaking the law. Register anyway — it removes the compliant half of the volume.

Should I press a key to be removed from the list?

Not on a call you did not expect. On an illegal robocall, pressing anything confirms the number reaches a real person and typically increases the volume. Hang up instead.

Do call-blocking apps work?

They help, using shared reputation databases, and they add a data-sharing consideration since they generally see your call log. Carrier-level screening does much the same job without an additional party.

What does blocking a number actually do?

It stops the call reaching your handset. The caller usually hears one ring then voicemail, and on many networks can still leave a message you are never notified about — which is why blocked callers sometimes appear to still be getting through.

Sources

National Do Not Call Registry — Federal Trade CommissionThe registry that outbound calling lists must be scrubbed against.
Telemarketing Sales Rule — Federal Trade CommissionDo-not-call obligations, abandonment-rate limits for predictive dialing, and required call disclosures.
Combating Spoofed Robocalls with Caller ID Authentication — Federal Communications CommissionThe STIR/SHAKEN framework, the attestation levels carriers sign calls with, and the mandate requiring providers to authenticate caller ID.

Stop working around the phone system

Carrier codes exist because the line was never built for a business. Owned numbers, routing rules, voicemail and recording in one place, priced on usage.

No seat licences
Numbers you own
Compliance built in

Get early access How legitimate calls stay unblocked