“Usable” is the correct spelling that is more commonly used. “Useable” is a correct variant spelling but is used less often. Both words are acceptable in any English-speaking country, and they’re both used to mean that someone is able to use something.

The short answer is that both spellings are correct. However, there are some nuances you should be aware of concerning when to use “useable” or “usable.” First of all, your location is a determining factor in which spelling you should employ. “Usable” without the extra “e” is the preferred way to spell the word in American English.

Internationally, both “usable” and “useable” are acceptable spellings of the word. Most dictionaries list “useable” as a variant spelling. You’re more likely to see it in places where British English is dominant.

Usable can also be spelled useable, with an e in the middle: both are correct. The US version simply lists useable as an acceptable variant of usable, and omits the side note.