What is the difference between a sleeper sofa and a sofa bed?

A thin, foldable bed lies underneath the cushions of a sleeper sofa's conventional appearance. These couches can easily have two people sleep on a full- or queen-sized mattress, depending on the width when the sofa bed mattress is fixed inside the furniture and cannot be folded down. It has one flat surface that can be folded at an angle to convert to a chair. A futon is the standard kind of sofa bed.