The question sounds simple, but "who called me" can mean four different things: where the number is from, what kind of line it is, whether other people have had calls from it, and which person or company is behind it. The first three are usually easy. The fourth is where people waste money, so it's worth knowing the limits before you start.

Read the number first

A UK number already tells you a lot. Numbers starting with 07 are mobiles, 01 and 02 are landlines tied to an area, 03 numbers are used by organisations across the country, and 080 numbers are freephone lines. A number starting with + followed by anything other than 44 comes from abroad. Our list of UK area codes and dialling codes shows what each prefix means and what calling it back would cost.

Check what other people have reported

Sales calls and scam calls don't ring one person. They ring thousands, and some of those people write down what happened. Searching the number on Who Rang shows those reports, how many times the number has been checked and the type of call people describe. For UK numbers, each number page also shows which network the number range was originally allocated to, based on Ofcom's numbering data. If a number is among the most searched numbers right now, it is almost always part of an active calling campaign.

Use the tools on your phone

  • Landline: dial 1471 to hear the last number that called you. It won't reveal a number the caller withheld.
  • Android: the Google Phone app shows business names and spam warnings for many numbers.
  • iPhone: check whether a missed call shows "Maybe" with a name taken from your emails or messages.
  • Voicemail: genuine callers usually leave a message, so check it before calling back.

What you can't find out

There is no public directory of UK mobile numbers, and networks don't tell customers who owns another number. Sites that promise a name and address for a mobile number after payment usually sell you the prefix, the network and a few comments - things you could see for free. If calls become threatening or persistent, the right route is your phone provider and, if needed, the police, who can obtain subscriber details through legal requests.

In practice, you rarely need a name. You need to decide whether to answer or call back, and the reports from other people plus the type of number usually settle that in under a minute. If you suspect the call was a scam, don't ring back from the missed call - read whether you should call back an unknown number first.