I made five of these today for the sofa! They turned out to be quick and simple to sew, and they fit well, mostly because I made a lucky mistake in the math during the planning stage. So I’m posting my first pattern here, mostly so I don’t lose it, but also so it can be useful to someone else.
They fold over the cushion in back, so it’s a quick on-off to wash and replace them. And you can display either side.
The pillow is Ikea’s Inner, size 16×24″. It’s probably cheaper to buy it than to make it yourself.
If you intend to make more than one cover, cut out a paper pattern, 21″ x 19″.
Lay it with the long side along the fold of your fabric, so that you get a rectangle, 21″ x 38″, unfolded.
Hem the short sides by folding them 1/2 inch toward the back of the fabric, and then folding again, 1/2 inch. (Use the iron to press the fold flat if your fabric is thick.) Pin and sew 1/4 inch from folded edge, and another seam 5/8 inch from folded edge.
Lay your cushion in the center of the printed side of the fabric:
And wrap it tightly to gauge how much overlap you need to keep the pillow snug inside. Don’t pull it too far, or you’ll end up with a gap in the middle of the opening when it’s done. The opening will be held shut at the sides only, though, so it should be a pretty big overlap.
About 4 inches of overlap worked well for me.
Make sure your new rectangle is squared-up, then pin the open sides shut, with the overlap pinned well. Double check that printed sides are together before you start sewing. (If you have a preference for which hemmed edge will show in the finished product, then the one you want on top needs to be on the bottom while you sew.)
Sew the pinned sides, 1/2 inch from raw edges. Be careful crossing the overlapped hems if your fabric is thick, or if your machine is on the feeble side (like mine, poor thing).
Then turn it right side out and stuff it with a cushion! Done!
You can even fussy cut it to include a fun motif, if you’re into that.