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How to Make a Duvet Cover Larger

Today I’m going to show you how to make a duvet cover bigger.  This spring I upgraded our old bedding from West Elm with two lovely linen bedding options: a coastal grey and white striped linen duvet cover, with white linen sheets, from Brooklinen (featured in this post), and a solid linen white linen duvet cover, with soft aqua linen sheets, from MagicLinen (featured in this post).  Both options are amazing – I highly recommend either, with one caveat: Brooklinen is sized larger, while MagicLinen is cut much smaller.  If you have a deep, generous mattress and fluffy duvet – go with Brooklinen.

Striped Coastal Duvet CoverStriped Linen Duvet Cover

My Brooklinen duvet cover also seems to wrinkle less.  But if you have a smaller mattress, or thin duvet, the MagicLinen is perfect – plus they have some gorgeous colors.  I have a large mattress, so the MagicLinen was a bit snug on my bed.  The fitted sheet didn’t tuck under completely and the duvet cover, unless I cheated it to one side, revealed the mattress along the bottom:

How to Fix a Duvet that is too small Duvet is too short - how to fix it

So I decided to hack the duvet cover, by sewing a band of fabric along three of the four sides, to make my linen duvet cover a custom size!  To save money, I cut up and used the fitted sheet (it didn’t fit anyway, and then it coordinated nicely with the flat sheet).  Here’s the before (cheated to the left to hide the smaller size):

How to make a duvet cover bigger

Below is how the duvet cover looks now.  Note: I didn’t iron – because who has that kind of time? – but also because I wanted you to see what it looks like fresh out of the washer and dryer.  I grow really tired of people faking food photography (with artificial ice and spray foam instead of whipped cream) and home decor and DIY photography (with endless Photoshop and impractical styling), because then we expect unrealistic results.  This band along the edge solved my length problem, but also drew attention to it being un-ironed.  Somehow the solid white hid the wrinkles better.  But it covers the mattress now, so I’m happy!

How do you resize a duvet coverDuvet cover shrunk how to fixAdd a contrasting band of color to a duvet cover Duvet cover hack

How to Make a Duvet Cover Larger:

First, we cut along three of the edges, leaving the buttoned side intact.  Cutting was easier and faster than seam ripping.

How to sew a flange on a duvet cover How to sew a flange on a duvet cover

Next, we cut up the fitted sheet.  I used the fitted sheet because 1) I already had it, 2) it didn’t fit the mattress well, anyway, and 3) it coordinated with the flat sheet, which I think makes the end result look more intentional and less like I hacked it.

You can purchase fabric for this – the amount needed will depend on the size of your mattress, and how much you need to add to the size of your duvet cover.  When figuring out the length for these strips of fabric, figure out your desired overall size (it helps to grab a duvet cover you do like and work off its measurements), leaving 5/8″ for seam allowances.

Choose a fabric in a similar weight – ideally, the same kind of fabric.  And pre-shrink in the washer and dryer to avoid any shrinking (and therefore puckering) later.

You can do two strips per side (a strip for top and bottom, sewn together), like we did, or do one wide strip that loops from the top side of the duvet cover to the bottom side.

How to sew a flange on a duvet cover

Because I used a sheet, I didn’t have enough length so we had to make this little square corner.  If you are buying fabric, you can skip this and make a mitered corner.

Add fabric to a duvet cover

Pin the new strips of fabric to the duvet cover, good sides facing together, and sew together, leaving a 5/8″ seam allowance.

How to sew a flange on a duvet cover Sew a duvet cover bigger how to make a duvet cover larger

To help the new panel lie flat, open the seam on the back and iron flat:

Enlarge a duvet cover

Then secure it in place with top stitching: just sew along the top of the new panel, and also the duvet cover, as close to the seam as possible, using coordinating thread.

how to make a shrunken duvet cover bigger

At this point we had this (the panels sewn onto the top of the duvet):

How to sew a flange on a duvet cover

Here’s our piecing for the corner (again, you won’t need this if you buy fabric for this project).  You can, instead, sew a mitered corner here.

How to sew a flange on a duvet cover

We repeated the above steps on the bottom of the duvet cover and then sewed the top and bottom of the duvet back together.  Again, you can skip this too.  You could cut strips wide enough that it loops from the top side to the bottom side, and then you only have to sew the panel onto each half of the duvet – not onto each half and then together, like we did.

How to sew a flange on a duvet cover How do you resize a duvet cover

We only added length to the three sides because it was WAY easier not to have to take apart and re-sew the button closure.  When I make my bed, I tucked that under my fitted sheet anyway.

How to sew a flange on a duvet cover

If you have a serger, you can serge the sewn edges to prevent unravelling.  If not – you’re DONE!  That’s all it takes to make a duvet cover larger.

How to sew a flange on a duvet coverwhy is the duvet cover smaller than the duvet

P.S. Don’t Forget to Pin for Later!

How to Make a Duvet Cover Larger



  1. Anna
    September 5, 2021 / 3:17 pm

    You not only added size to the duvet cover, you added style. It’s lovely.

  2. Oona
    October 4, 2021 / 1:24 pm

    Hi, Tanya. I’m getting caught up on blog posts today and am loving your solution to undersized bedding. This is especially helpful for king-sized beds, where you can’t size up. (We recently downsized from king to queen sized mattress, and I’m still using our king duvet and quilts on the new bed. They actually look better, and they cover us totally so we don’t have the midwinter tug-of-war with the blankets on cold nights!) I do love the look of the coordinating sheet color band on the duvet cover, and am thinking I could use this idea to make a new cover from some full-sized sheets whose color I love but that don’t fit our current bed. Sounds like a good winter project. Thanks for the idea!

    • October 4, 2021 / 5:11 pm

      I love the idea of using king sized duvets and quilts on a queen size mattress – that’s so clever! Bedding is rarely generous enough so that’s such a good solution.

  3. Colleen
    March 15, 2022 / 10:55 pm

    The duvet cover is bigger but if the duvet is the same size, doesn’t that just leave the corners empty? We just upgraded from a queen bed to a king, but I’ve used a king duvet for years and though it was wonderfully long on the queen bed, it is woefully inadequate for the king mattress in my opinion. I’m on the hunt for an oversized king duvet but the thoughts of giving up my beloved fluffy Irish duvet makes me sad…

    • March 16, 2022 / 4:57 pm

      For me, before we enlarged the duvet cover, the duvet itself was really bunched up inside. It felt cozy and fluffy, but it was just much more tightly packed than I am used to, lol. And the biggest issue for me was that, when centered, the duvet/duvet cover didn’t cover my mattress so you could see it when the bed was made. I just prefer my duvet covers a certain size, and that’s totally subjective. I hope you find the duvet of your dreams! I wonder if you could somehow hack two together to make the ultimately king sized duvet? Maybe just add some duvet pieces to the perimeter of your existing one?

  4. Joyce
    January 6, 2023 / 11:53 pm

    I’m about to make a queen size duvet cover with 2 king size flat sheets. I’d like to add a 3” flange incorporating a hidden button placket to close it at the bottom. I don’t want to lose the puffiness of the comforter. Any suggestions?

    • January 7, 2023 / 12:47 pm

      I’m so sorry, but I don’t understand what kind of advice you’d like from me?

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