This mattress wasn’t firm at all. Honestly when you go to Sid on the edge of it you almost slide right off because it’s so soft. I am a side sleeper and when I laid down to sleep, my hips sunk down so deep that it caused me lower back pain. I’m 5’5 and 135. Not overweight but I do have an hourglass shape which is why my hips must have sunken so deep. I also found myself overheating with this bed, which has never been an issue in other beds. My husband didn’t seem to have the same sinking issue but he agreed it was too soft and we returned. The return process was simple though.