Q: Which of these expressions is correct, “fine by me” or “fine with me”?
A: They’re both correct. “Fine with me” is perhaps a bit more formal, but “fine by me” is good colloquial English.
Of the two expressions, “fine with me” would seem to be somewhat older, at least according to the published references in the Oxford English Dictionary.
The first citation for the phrase in the OED is in a 1917 book that defines “thumbs up” as “everything is fine with me.”
The earliest citation in the OED for the “by” version is from a Feb. 3,1968, article in the Globe & Mail of Toronto: “It’s fine by me; I quit a couple of years ago.”
After a bit of noodling in old newspaper archives, however, I found earlier examples of both expressions.
A Dec. 22, 1901, article in the Idaho Daily Statesman about Christmas shopping quoted a Boise druggist as saying, “Business has been fine with me all of the past week and Monday and Tuesday will be much better.”
And, by and by, the other version showed up in a 1937 Walter Winchell column: “Those precocious Abbye children who wrote a book are going to tour China in a trailer … That’s fine by me.”