Learn when it's appropriate to use OK vs. okay vs. O.K. with Grammar Rules from the Writer's Digest editors, including a few examples of correct and incorrect usages.
I mean, I hope it's all right to address the controversy in this post and finally (FINALLY) declare a winner in this battle royal of appropriate usage of how to say something is A-OK.
OK vs. Okay (vs. O.K.)
OK is actually the more established form of saying things are okay. It first appeared in the United States in the 1830s as an abbreviation of a misspelling of the phrase "all correct." And it's the preferred usage as established by the AP style guide. So winner-winner, chicken dinner. Only...
Okay, which means the same thing, is the preferred spelling of the term by the Chicago style guide. And both are used all over the place, so...
It's seriously all right to use either OK or okay unless you're writing for an editor who adheres to AP or Chicago style. Then, it's only OK (or okay) to use their preferred version Gah!
And then, there's O.K. It's okay (or OK) too, except I'm making a personal request that people do not use this spelling, because why do you need those extra periods? Seriously.
And when it comes to A-OK, it's an abbreviation of "all OK," which I guess means it's an abbreviation of a misspelling of "all all correct," which is redundant. So, whatevs. At this point, you're going to do what you're going to do, and maybe that's okay [(or OK) or A-OK].
Just please be consistent, so that if an editor is not OK with your spelling, she can perform an easy search and replace to make everything A-OK.