What is the best format for a full 10-digit U.S. phone number in terms of readability, accessibility, and overall ease-of-use?
A few examples:
- (800) 555-1234
- (800)555-1234 (no space after the area code)
- 800 555-1234
Personally I think the first option is best but I can't pinpoint why. I also wonder whether the inclusion of the parentheses adds helpful cues or causes cognitive overload and/or distraction.
The target audience is the general public and the users are almost all American residents. The phone numbers are normally displayed on a web site alongside other data such as a street address.
Many of these numbers were entered by the user and are being displayed back for verification purposes. The users are allowed to enter the number in any format; on the server, we strip all spaces and punctuation and store only the 10 digits.