Turn a Flat Sheet into a Fitted Sheet in Ten Minutes Flat

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.

Written by Julie Finn

I'm a writer, crafter, Zombie Preparedness Planner, and homeschooling momma of two kids who will hopefully someday transition into using their genius for good, not the evil machinations and mess-making in which they currently indulge. I'm interested in recycling and nature crafts, food security, STEM education, and the DIY lifestyle, however it's manifested--making myself some underwear out of T-shirts? Done it. Teaching myself guitar? Doing it right now.

Visit my blog Craft Knife for a peek at our very weird handmade homeschool life, and my etsy shop Pumpkin+Bear for a truly odd number of rainbow-themed beeswax pretties.

1. Thanks, never ever would have thought of this idea

2. this is the first time I have seen your blog. This is a good idea ,but my mother-in-law was like martha Stewart and she figured out you could use the flat sheet by making a hem around the edges and just run elastic in the hem and draw it up and tie it off . and when you put the sheet on the bed it hugs the mattress and stays on good . better than bought fitted ones. And I use this method in making baby sheets. One yard cheap cotton and it's a great fitted sheet for the crib.My name is Anita. thanks for listening… peace

• Did she run the elastic all the way or just at the ends/corners?

• Just run the elastic at the corners. It should end up looking pretty much like a store-bought fitted sheet, which also has elastic only at the corners.

• Thank you Anita!!! I’m making a fitted sheet for a 36 x 36 play pen for my friend. Each sheet on Amazon was \$30 each!! And thank you Julie for this webpage!

So thankful, Susan G

3. Ooh that's a great idea! Our fitted sheets always wear out so much faster. Thanks so much for this, I'll be linking.

4. I'm kind of into this idea these days using vintage sheets, too. I really like the look of mismatched, busy (but sorta coordinating) bedding, and vintage sheets are GREAT for that.

5. This is a great idea! We just got the Contour Adjustable King duo bed (which is actually 2 XL twin beds…..future buyers beware!) so I need 2 fitted XL twin sheets and 1 king flat sheet…..VERY hard to find pretty patterned fitted sheets unless they are in a set. This great idea will save me both time and money. Thanks ever so much again…..BTW….you might need to adjust the measurements if you have deep a deep mattress.

6. Hi:
Am I the only one who had trouble with this? I tried following the directions and ended up with a fitted full size sheet that was about 6 inches too long! I re-read the directions and it seemed to me that I needed to go back to the step where you subtract the size of the mattress from the size of the sheet and THEN to subtract the smaller number from the bigger and cut that extra sheet length off the end and hem the sheet end. I tried that approach on another sheet and that worked out fine. It seems like its the only way to be able to take a perfect square out of each corner.

• I used the basic technique to convert a twin flat to a twin fitted and also had to trim one long side and hem it before cutting all four corner squares.

• I am in Tasmania. Just followed instructions using queen flat sheet with measurements 101″ x 95′
Fitted sheet now far too wide! What to do? Bed measures 79’x60

7. I am making a twin fitted sheet with fabric that is 62 inches wide. The depth of my mattress is 11″. What would my corner cut off be? I think l2 1/2. Is my fabric wide enough for a twin bed measuring 37×75? I bought three yards.Thanks. Will wait for a reply.

• 12.5″ sounds right to me. If you have the mattress, you can also try stripping the mattress and draping your fabric over it–it won’t give you the specific measurement, but you can see the drape and get a good estimate that will let you know if you’ll like 12.5″ or not.

8. wondering if this same technique will work to make a cover for a chair cushion.

9. Thanks a million for this tutorial, I desperately need to remodel some sheets and this makes it so clear and easy!

10. Hello. Does anyone know how to remake single fitted sheets into king single fitted sheets? I have just bought a KS bed. Thanks

• Sew two twinxl flat sheets togeather at the side of the sheets.

11. My bed is a bariatric bed. It’s larger then a twin but smaller then a full. Just a fitted sheet alone costs more then i can afford. So if I use a full side sheet to make my fitted sheets, when i measure do i take into account the sides in or just edge to edge across the top to trim?

• I’d say use a full sized flat sheet, yes. Here’s what I’d do:

1. Measure the length (L)of your mattress, the width of your mattress (W), and the depth of your mattress (D).

2. Figure out how much extra to allot for seam allowance.

3. Starting from one corner of your flat sheet, trim it to the following measurement (L+D)x(W+D).

4. Hem the raw edges.

5. Follow the tutorial as written.

• I would change #3
Trim to measurement
(L+2D) x (W+2D)

• L+D+seam and hem allowance and W+D+seam and hem allowance.

• 2D accounts for the depth on both the head and foot ends and on both sides.

12. LOVE this tutorial – thank you 🙂 I whipped a fitted sheet up in no time yesterday (not 10 minutes…however that is to be expected with 4 kids running around!), excitedly went to put it on the bed and…it is too wide! Top to bottom fits perfectly on one side and then when I go to put the other side on the corners are about 20cm away from the corners of the mattress. I have checked and rechecked my measurements and have NO idea where I went wrong. I would assume it would have to be a measurement issue but I can’t see how/where!

• I’m assuming that after you did the subtraction of sheet length-mattress length and sheet width-mattress width that you didn’t come up with the same number for both equations, right? If you got two different numbers, you used the smaller number for your measurements, because you wouldn’t want your fitted sheet to be too snug. But whichever side corresponds to the bigger number is going to be a little roomy, an issue that the sewn-in elastic should resolve by pulling all the sides down and under the mattress. The issue can also be resolved, however, by trimming the side with the bigger number so that an identical cut is the perfect cut for all sides.

13. My husband and I just made a custom bed and I’m trying to figure out how to make custom sheets. The bed is 108×75, someone please help. A king size isn’t quite big enough to do what you suggested with a flat sheet. Thanks for any help.

14. Here’s another thought…if you do use both flat and fitted sheets but have a hubby or child that pulls the flat sheet out from the bottom all the time…..just make the two bottom corners of the flat sheet into two fitted corners and you will more than likely solve the problem! We have a very deep mattress because I need a lot of padding on top to be able to get comfy (muscle issues) and so many of the flat sheets that I can afford don’t give me much to tuck in at the bottom – hence they pull out with just a tug or two. So, sewing the bottom two corners really helps to keep the sheet from pulling out. Hope this helps someone!!!

• Old water bed sheets for the size of your mattress will work. My husband hates his feet being held down, but I don’t like mine untucked. The waterbed sheet has the edges free for him and I sewed mine. They are sewed across the bottom and I loved them before they got torn and had to be recycled into a kid’s set.

15. I followed the instructions and re-read to make sure, and I ended up with a sheet that is too wide. Not sure what I did wrong. Please help.

16. This tutorial has worked perfectly for me several times, on several different bed sizes. I don’t think it needs to be anyone’s job to troubleshoot for you. Surely you can figure out for yourself what’s going wrong?

• A little blunt are we?
I don’t think it is anyone’s job either, just asking for advice. No need to reply Jane.

• Sarah , I just put my sheet on the matress and drew it off with water markers, it need not be perfect .

• Jeesh! Fortunately, these types of blogs that offer tutorials are put together by such lovely, helpful crafters! Unfortunately, some of its users still haven’t learned “if ya don’t have anything nice to say….” Its bothersome that you felt the need to say anything Jane!

17. I am trying to make a fitted sheet for a dolls bed ..Foam meassures 13w x22Lx 2D……What size material should I use in order for it to fit well..Thank you
E Loy

18. This is also a GREAT way to keep your flat sheets on the bed. You can turn the bottom corners into fitted pockets and your flat sheet won’t come untucked and hubby can’t steal ALL of the sheets from you 🙂

19. Just turned an old fitted Queen Sheet into a fitted sheet for our double sofa bed. The mattress size on the sofa bed is smaller than a normal double and the standard fitted double just wouldn’t stay on the mattress. The old queen had a hole in one end but I had enough material to get the new sheet out of it. Your directions are wonderful and I used a serger which made it even quicker!!! I also made crib sheets for my grandson out of wonderful fun material…

20. I LOVE these ideas !!! We added a 4″ memory foam to our king bed and I have fitted sheets that give me a total work-out when making the bed.I have looked everywhere for just fitted sheets and when I di find them they are 40-50.00!!!!!

Thanks for all the ideas !!!!

21. If all else fails in sewing, buy some men suspenders and connect sheets on the bottom of the mattress ……saw it on the internet but havent tried it.

22. Hi! Just want to say that I was so pleased to find your “How to” tutorial on turning flat sheets into fitted sheets. I’m also happy to hear that our’s is not the only family that wears out our fitted sheets first! Maybe I have the sewing skills to do this . . . maybe!

What kind of sewing machine would you recommend for a beginner (going back to sewing after many years!) who wanted to do this kind of project? – preferably with a nice vintage sheet! (Love ’em!)

• I’ve got a pretty old Bernette with a metal exterior that was given to me about a decade ago (after having been used for who knows how long) that’s still going strong, and a newer Singer that just broke after five years of constant use (although that one was used, too, and of course I didn’t use my Bernette much while I had the Singer!). I’ve never used one of the really new machines, although now that I’m down to *only* one machine, I’m definitely toying with the idea.

For a beginner, I’d recommend going mid-range. You don’t want bottom of the line, because they’re mostly made up of junk and meant to snooker in people who don’t know what they’re looking for, but most people aren’t ever going to use most of the features in a top of the line machine–heck, I didn’t use half of the features of my mid-range Singer! If it’s got the stitches that you know you’re going to use–back stitch, zig-zag, several stitch lengths–and it’s got good reviews, then I’d say go for it. The real test is putting the time in to teach yourself how to use your machine–even now, I still sometimes refer to my sewing machine’s manual for something or other.

• I use a totally basic sewing machine from walmart (was just under \$100). Works well for me…I just do basic things though like sewing repairs and easy straight stitch stuff ie. Hems….though I have stitched a couple costumes together for my son as well 🙂

23. I have not tried it but some suggestions would be put the sheet on the bed the right side down pin the corners together down the side of the top mattress then take off a sew.

24. I would recommend, before cutting, try doing a few rough stitches(I do very rough stitches with help of needle) , keeping the unneeded cloth inside and try fitting it.once it looks good, then cut/fold inward like a triangle and follow the process . Gives scope for errors, In case your mind changes, you might want to convert it into a flat sheet again..or may be ant to give another size..cutting will make almost impossible.

Also, if you cut the cloth, keep t aside and mx n mat h appliqué on various bedsheets

25. I used to kick my top sheets out of the bottom of the bed, until I bought a cheap sheet and ripped it into 4 pieces, hemmed them and then sewed them to the bottom edges of my top sheets. So now I have extensions on the sheets, which give a large amount of tuck-under that even I can’t kick out in my sleep. These extensions aren’t wide enough to go all the way from one side of the sheet to the other – I just center their edge to the sheet’s center edge which gives ample width for tucking in.

26. Love this site, but it does not give me a solution to my problem. I bought single bed fitted sheet but it is too short. How do I make it longer?? Terri

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