“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.

Useable suggests an object's practicality and convenience for a certain purpose, hinting at ease of use or suitability for a specific task. Usable, on the other hand, emphasizes the capability of an object to be used, regardless of how convenient or practical it might be.

The words "useable" and "usable" are often used interchangeably in English to describe something that can be used. "Useable," although less common, is an alternative spelling that has the same definition. The distinction between the two is mostly a matter of preference and frequency of use, with "usable" being the more prevalent form.

Many words in English have more than one spelling, and there are various reasons why this can be the case. In terms of American English, “usable” is the most acceptable version. Internationally, both “usable” and “useable” are acceptable spellings of the word. Most dictionaries list “useable” as a variant spelling.