I’ve been cutting, sewing and stuffing cushions for more years than I’d like to mention and I’m coming from an upholsterers standpoint in this article. Getting the perfect fit every time is important. The easiest way to get a perfect fit is to start with a template for a piece that may have angles and curves or the exact measurements for a piece that is square or rectangle. It may sound elementary, but many times a customer will come in with just the foam and want me to make a cushion without measurements or a template. You simply can not get the correct fit that way.
One method I use in the upholstery shop when I’m cutting cushions for an upholstered piece I’m working on is to remove the top of an existing cushion that fits properly and steam it back to it’s original shape for a template. I do this mostly for back cushions. I generally like to start off with a new template for seat cushions.
The perfect cushion starts with the perfect cut. The perfect cut starts with a perfect template or measurements.