How do I get the bounds of a sprite on its sprite atlas?

I used to make sprite atlases manually and set the texture's sprite mode to multiple, this let me use sprite.bounds.size to get the size of the sprite on the texture. Now I use the 2017 Sprite Atlases and set every individual texture's sprite mode to single, but sprite.bounds.size just returns the original texture size. Any idea how to get the size of the sprite's box on the sprite atlas? Thanks!