Mixing up “who” and “whom” can be easy to do. The good news is you can implement one simple rule to determine which one is the best word to use. Utilizing this helpful tip can help you cut down on the number of times you misuse these two pronouns.

Definition of “Who”

“Who” is considered a nominative or subjective pronoun. In other words, you can use “who” as the subject in a sentence. “Whoever” also follows the same rule. “Who” is used only for human beings, not for things or nonhuman animals.

Definition of “Whom”

“Whom” is an objective pronoun. It acts as an object in the sentence, not the subject. The same goes for “whomever.” Again, “whom” should only be used to refer to a human being.

When to Use "Who"

Use “who” as the subject or as a complement to a linking verb. To double-check your accuracy of using the word, substitute a personal pronoun, like “he” or “she” for “who.” If the sentence is grammatically correct with the substitution, then “who” is what you’re looking for. For example, “Sarah was the woman who wore the cute black boots” can be tested for accuracy with “She wore the cute black boots.”

When to Use "Whom"

Include “whom” as the object of a preposition or as the object of a verb. When you are unsure, use the substitution rule. If “him” or “her” can be substituted and the sentence works, use “whom.” You can turn the subjunctive clause around, if necessary, to test your sentence. For instance, “Billy is the guy whom I asked to watch my dog while I was away” can be tested with “I asked him to watch my dog while I was away.” It wouldn’t work if the sentence was “I asked he to watch my dog while I was away.”