A sofa bed or sofa-bed, (in the US often sofabed, hide-a-bed or sofa-sleeper), typically is a sofa or couch which has underneath its seating cushions a metal frame and thin mattress that can be unfolded or opened up to make a bed. A futon differs from a sofabed, although sofa beds using futon mattresses are common.
Sofa beds can be found not just in many styles, but many sizes as well. They are categorized accordingly, from Chair Sleepers (cot size bed) to Queen Sleepers. Almost all sofa beds contain the standard bar and canvas mechanism seen for years, however a few new lines can be found with alternative mechanisms.
Sofa beds are usually three person couches. However sofa beds that are two person couches are also available. These types of sofa beds are known as love seat sleepers. They are known as love seats since the smaller size means you need to be comfortable with how close you will be to the person next to you.