When do you use different from or different than in grammar?

Answer 1

One often hears people cite a "rule" that you should always say "different from." However, both "different from" and "different than" have been in well-attested use for at least 350 years. Both wordings are correct and are standard English in both the United States and Great Britain, and you should refer anyone who tries to convince you otherwise to consult the Merriam-Webster Dictionary of English Usage or look up "different" in the Random House dictionary or any other large dictionary and note the usage notes there.

Take 2 - It is generally accepted that the use of from is grammatically correct. The constant or historical misuse of a word does not make it correct.

Answer 2

In grammar, "different from" and "different than" are both correct and can be used interchangeably. However, "different from" is more commonly used in American English, while "different than" is more commonly used in British English. So, the choice between the two depends on the variant of English being used.