To get the right size cover for a chair or couch, you will need to measure: The length of the item from the outer edge of one arm to the outer edge of the opposite arm.  The depth from the front to the back. The height of the piece from the floor to the top of the seat cushion. These three measurements should give you the information you need to gauge the appropriate size for a furniture cover. You may also need to measure the height of the chair or couch's back for some items. Check the manufacturer's recommendations for a sofa, loveseat, or chair cover to make sure it's appropriate for your furniture.  If you're looking for something easier to fit, consider a furniture protector rather than a furniture cover. This lays on top of the furniture but does not envelope it completely.