On the contrary and on the other hand

These expressions have different meanings. On the contrary is used to contradict. It is used to say that what has just been said is not true.

First speaker: I suppose the movie wasn’t interesting.

Second speaker: On the contrary, it was fantastic. I absolutely loved it.

In an informal style, you can express the same idea using actually.

First speaker: I suppose the show was interesting.

Second speaker: Well, actually, it was a complete waste of time. (Less formal than ‘On the contrary it was a complete waste of time’.)

On the other hand is used to give the other side of the question.

She lacked experience, but on the other hand she was hard-working and willing to learn.

On the other hand and by contrast

My parents lived in the same village all their life. By contrast, I have traveled extensively.

Both by contrast and in contrast are used to compare two people or things and to say that the second one is different from the first one.

• There is a remarkable drop in the sale of printed books. Ebooks, by contrast, are selling quite well.

Note that the same idea can also be expressed using the adverb on the other hand.

• There is a remarkable drop in the sale of printed books. Ebooks, on the other hand, are selling quite well.

In contrast to and by contrast with

We use in contrast to before a person and by contrast with before a thing.

• In contrast to his father, he has an appetite for travel. (= His father was not really interested in traveling, but he is.)