Need a fitted sheet? Here’s how to turn a flat sheet into a fitted sheet to beef up your bedding stash.

We are very hard on fitted sheets around these parts. It’s likely a combination of all the playing, sleeping, wrassling, and, yes, jumping that gets done on top of them every day, the result of which is a bunch of fitted sheets with worn spots and rips along the seams and plenty of stains from ink pens and grape juice.

In contrast, we don’t use our flat sheets very much. Pretty much everybody in the family prefers a very light blanket, or nothing, to being covered with a sheet so often we don’t even take them out of the drawer.

What we’re left with, then, are too many flat sheets and not enough fitted sheets. If you have the same problem, or if you just happen to have a gorgeous vintage flat sheet or two that you’d love to make use of, then have I got a solution for you! Read on to see how I turn my unused flat sheets into the fitted sheets, in very little time and at no extra expense.

You will need:

A flat sheet sized for your bed. If you have a queen-sized bed, for instance, you can make a queen-sized fitted sheet out of a queen-sized flat sheet, and it’ll fit your mattress perfectly. Use a king-sized flat sheet, however, and you’ll likely want to do some trimming.

Gridded cutting mat and scissors for fabric

Sewing machine with an appropriate needle and matching thread installed

Four six-inch lengths of elastic, at least 1/2″ wide or wider

1. Do the math to figure out how much you need to trim from each of the four corners of your flat sheet. You want to trim away a square piece of fabric from each corner, to bring the size of your flat sheet down as closely as possible to the size of your mattress. For instance, the average full-sized mattress is about 54″x75″. The average full-sized flat sheet is about 81″x96″, although if you’re using a vintage sheet or a sheet made of jersey knit, there can be some stretching that will increase this measurement.

Subtract your mattress length from your sheet’s length, and your mattress width from your sheet’s width, to learn the amount of extra fabric that your sheet contains in length and width: 81″-54″=27 for instance, and 96″-75″=21″. Divide the smaller number in half (10.5″). That number is the magic number. At each of the four corners of your flat sheet, cut away a square that measures that number. That way, your new fitted sheet will fit your mattress nice and snug one way, and be just a little looser the other way.

If the difference between the extra fabric in length and width is greater than a few inches, you may want to trim off some extra to bring that bigger number down. For instance, the difference in extra fabric in length and width in this particular sheet is 6 inches, which isn’t too bad and won’t make the fitted sheet too loose in the width. If the difference was something like ten inches or more, however, I’d trim the width down first for a snugger fit. Or not, because I’m not picky.

2. After cutting away the square, bring together the two cut ends at each corner and sew them up, making a pocket out of each corner of your sheet.

3. Sew the elastic to the hemmed edge of your sheet at each corner, stretching it as you sew.

Now you have a fitted sheet with elasticized corners. Make your bed with it and commence sleeping.

Or jumping.