How to check a caller ID before you trust it

Why it's hard to tell

It feels natural to trust the screen. The trouble is that the display shows only what the caller's system chooses to send, and scammers can set it to almost anything.

The Federal Trade Commission explains that scammers can make any name or number appear on your caller ID. A call that looks as if it comes from a government agency, or from a local number, may be coming from anywhere. A guide from GOV.UK says the same thing in plain words: do not trust caller ID on phones, since numbers can be spoofed.

Common tricks used

• Showing a real agency or bank name, so the call looks official before anyone speaks.
• Matching the first digits of your own number. The FTC calls this neighbor spoofing, and it is designed to make you think a neighbour or local business is calling.
• Using a number that really belongs to someone else, so a call back reaches a stranger.
• Leaving a recorded message that tells you to press a key or call a number.
• Asking you to confirm who you are before they say who they are.

How to verify, step by step

1. Do not press any keys on a recorded message. The FTC advises hanging up and not pressing numbers, since that can lead to more calls.
2. Say nothing about yourself. Do not confirm your name, address, date of birth or any account detail to an unexpected caller.
3. Hang up. If you are on a landline, wait a minute or use a mobile for the next call, because a line can sometimes stay open after you put the phone down.
4. Find the organisation's number yourself. Use the number on the back of your card, on a recent statement, on your own paperwork or on the official website you type in yourself. Do not use a number the caller gave you, and do not use redial.
5. Call that number and ask whether anyone has been trying to reach you. If there is a genuine matter, they can see it.
6. Write down what happened: the number on the screen, any number the caller asked you to ring, and the date and time. This helps if you decide to report it. The FTC asks for the number that reached you, the caller ID number, any callback number and the time of the call.
7. Report it. In the United States that means ReportFraud.ftc.gov if money was lost, or DoNotCall.gov if it was not. Our guide to how to report a scam in the US walks through the choices, and the UK version does the same for readers there.

For a government call in particular, the steps are the same but the number to use comes from the agency's own website. Our guide to checking a government call covers that.

Things to watch

• A caller who does not want you to hang up and check.
• Any request for money, a code or a card number during an unexpected call.
• A call that creates a deadline, such as saying something will happen today.
• A request to call back a different number than the one on your screen.

Call blocking can lower the number of unwanted calls but does not catch them all, so hanging up and ringing back remains the most dependable step. If you shared a code or let someone into your device, read what to do after you shared a code or gave someone access.