When do i capitalize sir and ma'am?

Answer 1

You will only ever capitalize sir when it is a title.

Example:

Sir Elton John

You will only ma'am when it is the beginning of a sentence (it is never a title).

Example:

Ma'am, you are dismissed!

Answer 2

You capitalize "Sir" and "Ma'am" when they are used as a direct address, such as "Yes, Sir" or "Thank you, Ma'am." In other contexts, like when referring to a person in third person, you do not capitalize them, as in "the sir at the counter."