Let’s discuss telephone number etiquette and try to answer the question “how to format phone numbers.” Some use periods (dots) between the parts of a telephone number while others use parentheses and hyphens.
Which style or format is correct? As usual, style guides differ. The Gregg Reference Manual takes the most liberal approach. Gregg offers many possibilities, illustrated here:
206-782-8410 This format is most common, according to Gregg.
(206) 782-8410 This style is common, says Gregg, but can’t be used when the telephone number itself appears in parentheses. Also, this format makes less sense in large metropolitan areas in which the area code is required even for local numbers.
All these are acceptable on letterhead and business cards, according to Gregg:
206 782 8410
To connect the parts of international phone numbers, Gregg uses hyphens.
Another style guide, Microsoft Manual of Style for Technical Publications, recommends parentheses around the area code, with the parts of the local number separated by a hyphen, like this:
Microsoft labels the all-hyphen style as incorrect and does not even mention periods or dots.
Related: you can read our review of the Microsoft Manual of Style, 4th Edition here.
For international numbers with country and city codes, Microsoft uses one set of parentheses around the country code followed by a second set enclosing the city code, like these codes for London, England: (44) (71). These numbers in parentheses are followed by the local number rendered in the style used by the particular country.
The Associated Press Stylebook (AP) agrees with the Microsoft Manual–mostly. Like Microsoft, it rules that parentheses be used around the area code, with hyphens between the parts of a local number. However, AP uses one set of parentheses around both the country and city code, like this: (44-71) followed by the local number. AP advises against periods.
The Chicago Manual of Style offers no rules. It states only that parentheses are sometimes used around the area code but hyphens are more common.
The Canadian Press Stylebook uses hyphens.
How does one properly format a phone number? Based on my review of these reference books, I would say hyphens are the best bet.
But there is something much more important than format.
Before printing a few thousand copies of a booklet or business card, before placing that costly ad in the newspaper, be sure the phone number itself is correct. Check it several times. Then have someone else proofread it. When readers want to phone you, the number itself is far more important than any style choice.