I have a new M1 14" MBP, and an old 2015(!) Intel 13" MBP. They are pretty much exactly the same height/width, if you put one on top of the other they line up

I have a new M1 14" MBP, and an old 2015(!) Intel 13" MBP. They are pretty much exactly the same height/width, if you put one on top of the other they line up close to perfectly. The 14" just has less bezel. The M1 14" is thicker and heavier though.