1To make a mistake; to do something incorrectly (transitive).
漢字を一つ間違えて点数が下がった。
I got a lower score because I made one kanji mistake.
電話番号を間違えて友達に電話してしまった。
I dialed the wrong phone number and accidentally called a friend.
入力を間違えたので、もう一度送信してください。
I entered it incorrectly, so please send it again.
2To mistake one thing for another; to confuse or misidentify.
砂糖と塩を間違えてケーキがまずくなった。
I mistook sugar for salt and the cake turned out awful.
彼を兄と間違えて声をかけてしまった。
I mistook him for my older brother and called out to him.
暗くて顔が見えず、知らない人を店員と間違えた。
It was dark so I couldn't see faces and I mistook a stranger for a clerk.