Why is reupholstering so expensive?
It’s a time- and labor-intensive process that involves specialized skills. A well-done job can include stripping a piece to the frame, reinforcing the frame and the joints, replacing coil springs and zigzag springs—and that’s all before the cost and complexity of fill, padding, and fabric. The most common misconception is that reupholstering is just about fabric.
Nevertheless...Check out an invaluable fabric calculator fabric-calculator.com to help get you started.