Fax Number Format Guide
How to correctly format any fax number — domestic or international — so your fax reaches the right destination.
Quick Answer
For domestic US/Canada faxes, use the 10-digit number: (555) 123-4567. For international faxes, use the format: +[country code][city/area code][local number]. Drop the leading zero from the local number when adding the country code. Example: to fax London, dial +44 20 7946 0958 (not +44 020 7946 0958).
US and Canada (Country Code +1)
Format: +1 [area code] [7-digit number]. Example: +1 212 555 1234. When using Best Fax, you can enter the number with or without the +1 prefix — either 2125551234 or +12125551234 will work. The area code is always required, even for local numbers. All US and Canadian fax numbers are 10 digits (area code + 7-digit number).
United Kingdom (Country Code +44)
Format: +44 [area code without leading 0] [local number]. London example: +44 20 7946 0958 (the local format 020 7946 0958 drops the leading 0). Other UK cities follow the same pattern: Manchester +44 161 xxx xxxx, Birmingham +44 121 xxx xxxx. UK mobile numbers starting with 07 become +44 7xxx xxxxxx internationally, though mobile numbers rarely receive faxes.
Germany (Country Code +49)
Format: +49 [area code without leading 0] [local number]. Berlin example: +49 30 1234 5678 (local format: 030 1234 5678). Munich: +49 89 xxxx xxxx. Frankfurt: +49 69 xxxx xxxx. German area codes vary in length from 2-5 digits, and local numbers vary correspondingly.
Japan (Country Code +81)
Format: +81 [area code without leading 0] [local number]. Tokyo example: +81 3 1234 5678 (local format: 03-1234-5678). Osaka: +81 6 xxxx xxxx. Japanese fax numbers are very common in business — Japan has one of the highest fax usage rates in the world.
Australia (Country Code +61)
Format: +61 [area code without leading 0] [local number]. Sydney example: +61 2 1234 5678 (local format: 02 1234 5678). Melbourne: +61 3 xxxx xxxx. Australian area codes are single digits: 2 (NSW/ACT), 3 (VIC/TAS), 7 (QLD), 8 (SA/WA/NT).
Common Formatting Mistakes to Avoid
The most common fax number formatting errors are: forgetting the area code (US numbers always need all 10 digits), including the leading zero when adding a country code (use +44 20, not +44 020), missing the country code entirely for international faxes, using letters or special characters in the number (use digits only, with + for country code), confusing a voice phone number for a fax number (they're often different), and transposing digits. Double-check your recipient's fax number before sending — a single wrong digit means your document goes to the wrong place or fails entirely.
Toll-Free Fax Numbers
Toll-free fax numbers (800, 888, 877, 866, 855, 844 area codes in the US and Canada) can be faxed just like regular numbers. Format: +1 800 555 1234. Many large companies, government agencies, and institutions use toll-free fax numbers. They function identically to regular fax numbers from the sender's perspective. Best Fax treats toll-free numbers the same as any other number — no special formatting required.
Frequently Asked Questions
Do I need to include the area code?
Yes, always. For US and Canadian numbers, include all 10 digits (area code + 7-digit number). For international numbers, include the country code + city/area code + local number.
Can I fax a toll-free number?
Yes. Toll-free numbers (800, 888, 877, 866, 855, 844 in the US) can receive faxes. Enter them just like any other fax number with the full 10 digits.
What if I don't know the country code?
Check our international fax codes directory for a complete list of country codes with formatting examples for 50+ countries.
Do I need to include the + sign?
When using Best Fax, the + sign is optional for US/Canada numbers. For international numbers, including the + followed by the country code is the clearest format. Best Fax will interpret the number correctly either way.
How do I know if a number is a fax number or phone number?
Fax numbers and phone numbers look identical — there's no way to tell them apart by format alone. You need to confirm with the recipient that the number is connected to a fax machine. Sending a fax to a voice-only number will result in a failure.
Can I use dashes and spaces in the number?
Yes. Best Fax ignores dashes, spaces, and parentheses when processing fax numbers. Whether you enter 2125551234, 212-555-1234, or (212) 555-1234, the result is the same.
What is the maximum length of a fax number?
Most fax numbers are 10-15 digits including the country code. The longest common numbers are in countries like Bangladesh (+880) or Nigeria (+234), which can be up to 14-15 digits total with the country code.
Ready to send your fax?
Now that you know the correct format, send your fax in under 2 minutes.