Both are types of furniture that can change from a seat to a bed. Sofa beds include a concealed bed. Similar to a standard mattress, the mattress of a sofa bed is often softer and thicker. In contrast, futon mattresses fold out from a frame and have a simpler design. Futon mattresses typically include firmer, thin foam mattresses. Futons work well in smaller places like studio apartments or dorm dorms, while sofa beds are ideal for living rooms and guest rooms. Therefore, consider your space and intended usage while making your decision!