Replace-Substitute | Commonly Confused Words

Replace

/rɪˈpleɪs/

To take the position of something else that was there before

Imagination has replaced reality.You talked to Gil Case about her replacing Terry King.Who replaces her Monday for the Philadelphia opening?"

/ˈsʌbstɪtjuːt/

A person or thing that takes the place of another

It was substituted for the other immediately after the murder.A substitute for a Fire.We each had a second bowl of the substitute rice.

Both words involve putting one thing in place of another, but they imply different relationships between the original and the new.
Replace suggests that the new item directly takes the place of the old one, often completely supplanting it.
Substitute indicates that the new item can serve the same role as the old one but may not entirely take its place, often suggesting a temporary or less permanent change.
Replace is often used when something is broken or no longer wanted, whereas substitute is used when the original is unavailable.
Think of replace as permanent and substitute as potentially temporary.