What does a fax number look like?
A fax number looks exactly like a phone number. There is no visual difference – a fax number is simply a phone number connected to a fax machine or fax service instead of (or in addition to) a regular phone.
Here is a US fax number example:
+1 (212) 555-1234
And here is what fax numbers look like in other countries:
| Country | Fax number example | Format |
|---|---|---|
| United States | +1 (212) 555-1234 | +1 + area code + 7 digits |
| United Kingdom | +44 20 7946 0958 | +44 + area code + local number |
| Germany | +49 30 1234 5678 | +49 + area code + local number |
| Japan | +81 3-1234-5678 | +81 + area code + local number |
| Australia | +61 2 1234 5678 | +61 + area code + 8 digits |
| Canada | +1 (416) 555-1234 | +1 + area code + 7 digits |
| France | +33 1 23 45 67 89 | +33 + area code + 8 digits |
Every fax number follows the same structure: country code + area code + local number. The + sign means "dial your international access code first" – that is 011 in the US and 00 in most other countries.
How fax number formats differ by country
The differences come down to three things: how many digits, how they are grouped, and what prefix you dial.
Digit count varies. US and Canadian fax numbers are always 10 digits (after the country code). UK numbers can be 10 or 11 digits depending on the area code. Japanese numbers range from 9 to 10 digits.
Local dialing rules differ. In the US, you add 1 before the area code for long-distance faxes. In the UK and Germany, you add 0 before the area code for domestic faxes but drop it for international. In Japan, the leading 0 works the same way.
Formatting is cosmetic. Dashes, spaces, and parentheses are just visual separators. Your fax machine ignores them. +1-212-555-1234, +1 (212) 555-1234, and 12125551234 all reach the same fax line.
For more detail on local, national, and international dialing conventions, see our full guide to fax number formats.
How to tell if a number can receive fax
You cannot tell from the number alone. A fax number and a voice phone number look identical. The difference is what is connected to the line, not the number itself.
A few ways to check:
- Look for a fax label. Business cards, websites, and letterhead often list voice and fax numbers separately.
- Call the number. If you hear a high-pitched tone (the fax handshake), it is a fax line.
- Just try sending. If the number is not a fax line, your machine will return a "no fax detected" error. Nothing bad happens to either end.
- Use a validation tool. Some services let you verify a fax number is active before sending.
For a deeper look at which phone numbers can and cannot receive fax, see Can I Fax to Any Phone Number?