The short answer
Pick the destination country first, then type the number without the country code, and without spaces or punctuation if you can. If you start with 00 or a plus sign followed by the country code, the form understands that too. Think of it as the reverse of dialing 011 from the US.
Check the number with the fax-number checker before paying. Local conventions for each country are described on the destinations page.
The three parts of a number
An international number has a country code (33 for France, 351 for Portugal, 1 for Canada, 49 for Germany, 34 for Spain, 39 for Italy, 32 for Belgium), then an area or network code, then the subscriber number. Because you pick the country in the form, you rarely need to type the country code yourself.
The classic slip is typing the country code twice. If the number you copied from a letterhead already begins with +33 or 0033, either remove that part or leave the country selected: the form copes with both, but check what it shows back to you.
The leading zero
Many countries put a zero in front of the area code for domestic calls, much like the 1 you dial before a US area code, and that zero drops out in international form. Italy is the odd one out: the leading zero of landline numbers stays. If a number fails, an extra or missing zero is the first suspect.
Remove spaces, dots, parenthess and dashes if the field complains. They are harmless to humans but a nuisance for dialing.
Check before you send
The number checker tests the length and structure against the rules of the country. It cannot know whether a fax machine is plugged in at the other end, so for something important, call the recipient and ask for the fax number to be read out.
A number that passes the check but still fails to deliver is often a voice line, a cell phone or a number that has changed. See what to do when a fax does not arrive.
Worth remembering
- Choose the country, then enter the number.
- Watch for a doubled country code and a stray leading zero.
- Use the number checker, then confirm by phone for important faxes.