Unscrew the seat from the frame of the chair. Most chair seats are held on with four screws that can be accessed by turning the chair upside down. Save these screws to use when reattaching the seat cushion.
Remove the existing fabric by pulling out the staples from around the bottom of the seat. Once the fabric is removed, the foam batting and cushion will be exposed.
Place the new fabric, wrong side up, on your work surface.
Place the chair seat, batting side down, on top of the fabric.
Beginning at 12 o’clock, pull the fabric toward you and staple to the seat. Put the next staple at 6 o’clock, then at 3 o’clock and finally at 9 o’clock, pulling the fabric tightly as you go.
Continue pulling and stapling the rest of the fabric, alternating from side to side, until all sides are completely attached. Save the corners for last.
Pull a corner of the fabric tight and staple it to the seat. There should now be two unstapled folds of fabric on either side of the corner. One at a time, fold them neatly and pull toward the corner staple. Attach to the seat with an additional staple. It may take a couple of extra staples to get the corners to lie flat.
Repeat for the three remaining corners.
Trim any excess fabric with scissors.
Place the seat cushion on the chair frame and reattach with screws.