How deep should a sofa seat be? Sit in one and see

A sofa can be the right width and colour and still be uncomfortable, because seat depth decides whether the edge presses into your knees or you sink back with your feet off the floor.

Change the height of a seated person and the depth of the seat, then add a back cushion to see the gap behind the knee shrink. Learn the usual shallow, average and deep ranges, why taller and shorter people need different seats, how to measure the sofa you already own, and the no-cost fixes for a sofa that is a little too deep or too shallow.