Measure the length of the seat of the couch. Have an assistant hold one end of the tape inside the left arm, right above the cushions. Pull the tape out to the inside of the right cushion and record the measurement.
Pull the tape measure out several inches to find the seat height. Hold the end of the tape measure at the bottom of a seat cushion. Record this measurement where the top of the cushion meets the tape.
Measure the base of the couch. Hold the end of the tape at the edge of the couch, about 4 inches under the seat cushions. Have an assistant pull the tape out. Mark down the measurement where the right edge of the couch meets the measuring tape.
Measure the couch at its widest points, according to Apartment Therapy. Hold the end of the tape at the edge of the left arm. Have an assistant pull the tape out and hold it up to the outside edge of the right arm. Write down the measurement.
Measure the depth (from front to back) of the couch for a cover. Hold the end of the tape at the left front corner, at the same height as the seat cushions. Pull the tape out and hold it against the couch. Mark down the measurement to the left rear corner.
Measure one of the arms of the couch to determine the depth for a cover. Hold the end of the tape at the front edge of the arm and run it out to the back edge. Record this measurement.
Measure from under the seat cushion to the floor (skirt width). Hold the end of the tape on the front center of the couch right underneath a cushion. Pull the tape down to the floor and write this measurement down.
Pull a seat cushion off the couch. Hold the end of the tape measure to the base of the cushion base. Have an assistant pull the tape out and over the back of the couch down to the floor. Mark down this measurement for the back overlay.
Measure the top of an arm on the couch at its widest point, according to Apartment Therapy. Next, measure the lowest part of the arm. Measure the height of the arm by holding the edge of the tape measure at the tip of the arm. Pull it out and record the measurement at the cushion base.
Measuring the depth of the seat cushion from its front edge to its back edge. Finally, with the cushion removed from the couch, measure from the cushion base to the top of the back of the couch.