How the validation works
We parse the number with Google's open libphonenumber rules and check it against the numbering plan of its country: whether the length is possible, whether the prefix belongs to a real range and what kind of number that range is used for.
A number that passes comes back in E.164 form (the international standard without spaces, such as +14155552671), in the national format people dial at home and in the international format people dial abroad.
Reading the result
The number type comes from the numbering plan: mobile, fixed line, toll free, VoIP and so on. Where a country does not separate mobile and fixed ranges, the result says so rather than guessing.
For US and Canadian numbers (+1) the area code and its region are shown. The region names where the code was assigned, which may not be where the phone is today.
The result says whether the number is valid, not whether anyone answers it. We do not query carriers, so we cannot tell if the number is active, ported or reachable.
Limits worth knowing
A number can be well formed and still be unassigned or disconnected. This tool catches typos, wrong lengths and impossible prefixes; it does not check live status or carrier.
The free tool handles one number at a time with a strict per-visitor limit. The API validates numbers in your own forms and imports.
Frequently asked questions
Does this tell me the carrier or whether the number is active?
No. The check uses numbering-plan data only. Carrier and line type come from the Carrier Lookup product.
What is E.164?
E.164 is the international format for phone numbers: a plus sign, the country code and the number, with no spaces or punctuation. It is the safest format to store in a database.
Why does a local number need a country?
A number such as 020 7946 0958 means different things in different countries. Add a country code or choose a country so we know which plan to check.
Why was my real number rejected?
Check for a missing digit, a stray trunk prefix such as an extra 0 after the country code, or a number format that changed recently. If you still believe it is valid, tell us at the support address in the footer.