When you say “barely fit” do you mean because you’re too tall or too obese? I can’t tell.
Anyway, I work in a hospital. We order specialty beds. I play a part in that too. Any patient who is taller than 6’5’’ usually is going to need a special bed that can be stretched out at the push of a button.
In my hospital, the regular beds support up to 500 lb. But most people getting up to that weight are rather wide and need a bariatric bed that is wider to accommodate their girth. Really depends on the person. I’ve heard of 400 lb people feeling comfortable in the regular beds but a very short 300 lb person needs a bariatric bed because their body is just too wide for the regular ones. It sort of depends.