Fax number checker

Choose the country, type the number, and find out at once whether it is ready to use.

Updated on:

A number able to receive a fax is a landline written the way its country expects. In Canada, ten digits in all: the area code, then the local line, for example 604 555 0182. This free checker applies the same test as the CaptainFax sending form, for Italy, Portugal, Canada, Belgium, Germany, France and Spain. It detects mobile numbers and repeated country codes and returns the international form.

Check a number

For example 0148817645 (Ten digits, the first pair being 01 to 05 or 09 (leading 0 kept); mobile (06, 07) and 08 numbers are refused)

Why a wrong digit costs you a retry

When a fax does not go through, the document is rarely the culprit. More often the number was slightly off: a digit lost when copying from a letterhead, a country code pasted on top of one already there, or a mobile number taken for the office line. The call then connects to no machine at all, and after a few attempts the send fails.

Conventions vary by country. Canadian numbers run to ten digits without a leading zero, and the 1 sometimes written first is merely the long-distance prefix. A Belgian landline has nine digits after the initial 0, while mobiles begin with 04. Italy is unusual in keeping its 0 when dialled from abroad, whereas France, Germany and Belgium drop theirs. The checker applies these rules and returns two versions: the national one for the CaptainFax form, and the E.164 one that most fax equipment and software expect.

It tests how the number is written, not whether anyone is behind it: a correctly formatted number might be disconnected or ring an ordinary phone. If the document matters, for instance a tax filing or a pharmacy prescription, take the number from the organization’s official site or from the most recent letter it sent you.

Fax number checker FAQ

Is the number I type saved?
No. It is checked at the moment you click and then discarded. No fax is sent and nobody dials that number.
Why does the checker reject mobile numbers?
A fixed line is required, with either a fax machine or a fax server behind it. Fax tones mean nothing to a mobile phone, so the call would end in ringing or a voicemail greeting, never in a printed page.
Does a green result guarantee delivery?
It guarantees the number is correctly written, which removes most causes of failure. The line must also be active and connected to a machine that is on. If a send still fails, check the number with the recipient.

Keep exploring

A few pages that go well with the one you just read.

Related questions