Determine the dimensions of a sleeper sofa by taking measurements of the sofa's height, width and depth, as well as the unfolded mattress space's area. Use a tape measure to find the number of inches along the longest straight lines across the sofa's surfaces.
Different dimension measurements can be used for different purposes. Standard dimensions can determine if a sleeper sofa will fit in a space. The standard dimensions use the largest measurements between points on the sofa, usually from the outside of one arm to the other, from the highest point on the back to the bottom of the feet and from the rear-most point on the back to the farthest forward point on the front.
The dimensions used to determine delivery ability are similar to the standard dimensions but use a different depth measurement. In this case, imagine a straight line from the top of the back to the front of the arm of the sofa, then measure from the bottom of the sofa back to the middle of that imaginary line. These dimensions determine if a tilted sofa will fit through a doorway.
To determine if the unfolded sofa will fit in a space, use the same measurements for width and height, but measure the depth from the back of the sofa to the foot of the mattress area. Determine the mattress dimensions by measuring the width and length of the surface under the mattress.