Knife Pleats and Box Pleats

Knife Pleats and Box Pleats

First of all Happy Almost Valentines Day!  That is why this particular post is obnoxiously pink and red :).  I hope you all have a wonderful day tomorrow!

Much like the last tutorial that I posted, adding a simple fabric folding technique can add a lot to any project.  This tutorial covers how to make some of my personal favorite handmade effects, knife and box pleats.  These particular methods are beautiful on clothes or decorative pieces. It can so quickly take a bland project and turn it into something special and unique.



We are starting with knife pleats because these are the basis of the other technique. Much like ruffles, they are not too difficult to create.  Knife pleats are perfect for making A-line skirts, or a detail on a shirt.

What you’ll need:

  • Fabric
  • Straight Pins
  • Sewing machine or needle and thread
  • Measuring implement
  • Calculator

The most difficult part of making a knife of box pleat is the math.  When you pleat or tuck fabric the length quickly diminishes.  Because of this, if you need a particular length, like if it has to go around a pillow or if you are pleating in a skirt you must do the math.   If you’re like me though you HATE math.  I really would almost prefer winging it and hoping for the best, knowing I may have to redo something.  That thought though has been mainly drilled out of me by parents/teachers/the fact that I also hate redoing things…  So instead we shall do math.  If you are doing a full 1″ knife pleat that means that the length of the pleat is 1″ and the tuck inward in also 1″ and the fabric under the pleat is 1″.  This means that each pleat will diminish the length of the fabric by three inches.  So if you need a skirt to have a circumference of 34″ (including seam allowances) then you would need 3 times that amount of fabric, 102″ (2.9 yards), of fabric.

So the equation would be:

(The amount of fabric you need to end up with) x (The full amount of fabric used by the pleat ie the amount of the pleat x3)

In the example of the 1/2″ pleat the math would be:

34 x 1.5

God, I hope that makes sense…  Please let me know if that only makes sense to me.  Since we’ve gotten past the math (in theory) now comes the fun part.  To make a knife pleat first begin by pressing back 1″ worth of fabric under.  Pin this into place.


From the edge of this pleat measure out one inch, then tuck under one additional inch and pin.  Continue this process until you have completed the length of fabric.  See!  I wasn’t kidding when I said the math was the hardest part!  When you’re done, simply sew the pleats down with a straight stitch across the pleats and you are done!




Box pleats are very similar to knife pleats.  The only difference is after you do a knife pleat in one direction, you then go out two inches (or twice whatever your pleat width is) and create another pleat in the opposite direction.  This means that the open portion of the two pleats should be facing each other.  This slightly changes the math.  You will then multiply the (amount of fabric you need to end up with) x (The full amount of fabric used by the pleat ie the amount of the pleat x6).


wine glass 1.5 1 1/2 glasses.  While the sewing is easy figuring out that math without the project in front of me (I was doing it in my head before I actually started the post) was kind of frustrating…and y’know wine is good 🙂

I hope that these three techniques help you to make beautiful projects!  I would LOVE to see what you make with these techniques! Keep Crafting!


13 responses »

  1. hi, i know you posted this like. a year ago. but. your knife pleat formula is wrong.

    your formula says that (desired length of fabric) x (total fabric per pleat) will give you the fabric you need, which is true, but the variables aren’t right. “(desired length of fabric)” is actually “(desired number of pleats”). it just so happens that the number of 1″ pleats will always always be equal to the length of fabric desired. i tried this formula with 2″ pleats (6″ of fabric), and it was totally wrong.

    following your formula, i plugged in the numbers i needed: (25″ desired length) x (6″) = 150. i ended up with a piece of pleated fabric that was 49″ long instead of 25″. what i did get, however, was 25 pleats.

    im still new to sewing, so im not totally sure if im right (and i’ve only tried this once), but a more accurate formula would probably be something like this:

    (desired width / desired pleat width) x (total fabric per pleat)

    so for example, something with 2″ pleats and a desired length of 25″

    (25 / 2) x (2 x 3 = 6)
    (12.5) x (6)
    (round 12.5 up to 13)
    (13) x (6)
    78″ total
    and then i guess you’d want to add seam allowance on either side?? (im not sure, especially with the rounding, but i figured you can’t really have half a pleat) again, im not totally positive that this formula is right (particularly with pleats that are smaller than 1″) so im sorry if it’s wrong.

    other than that, great tutorial! the pictures that you add to the step-by-step instructions really help beginners like me understand what it is we’re trying to do. thank you! i hope you’re having a good day! (:

    • I’m trying to figure out how much fabric I’ll need for a 27″ waist and making 3″ box pleats. Your math makes a little bit more sense than the person who made this tutorial, but I am still confused about part of it.
      Your formula is: (25/2)x(2×3) where did the three come from?

      • I know you posted this question a while ago, and you may have found a formula that works for you already. But just in case, here is how I figure out all m box pleated skirts.

        First, with box pleats no matter what measurement, or size of pleat, to get the material needed to make that one pleat, you multiply it by three. Because there are 3 “folds” in the pleats. the front, that you see when looking at the outside of the skirt, the back, when you look at the inside of the skirt, and the fold in between the front and back. That is to get the measurement for just on pleat. so 3*3 is 9″. So 27(you waist)/3(pleat width)*9(inches in a pleat)=81. So you would need 81 inches total for your skirt. For yardage, just divide that by 36.

        If pleats really trip you, and you don’t trust your math, find a tape measure; from the middle of that tape measure, decide your pleat width, and make the pleat in the measuring tape. Unfold the measuring tape, and count the inches used in the pleat. You will get your pleat amount. Then the math is the same; you waist (or wherever you wish the waistband to sit, waist or hip), divided by the pleat width, and multiply that number (you must do that first, keep this equation in the right order or it will mess you up) by the number of inches your pleat is, unfolded. This will get you the exact inches for your box pleated skirt. Knife pleated skirts are not the same, and this will not work exactly the same for knife pleated skirts.

        Remember this is the EXACT inches, this does not include seam allowance. so either add seam to your waist, or seam at the end to give yourself room. Also your measurements and pleat width are convenient because they are divisible to eachother. Normally these equations end with decimals. If you don’t mind a zipper you can see, as in attached to two sides of the skirt, with pleat next to them, add seam allowance at the end. If you wish to have the zipper hidden underneath a pleat, add before and make sure the end of the fabric ends up as the “back fold” of the pleat, so the “Front fold” of the pleat overlaps it. Then install a button or any closer you like to keep the pleat over the zipper.

  2. Thanks so much foe this great tutorial! I linked it on my blog because it was so concise i thought – “couldn’t say it any better myself so why try?” 🙂 thanks again!

  3. Pingback: A Christmas Tree Skirt… | Ribbon Jar

  4. Thanks for the tutorial! I’m currently following a pattern with little instructions so this has been a life saver when it comes to the knife pleats.

  5. thank you sooo much for this tutorial.I bought a pattern but it was more confusing than useful and I put off doing this skirt for my cosplay too long. I have 7 days to finish the whole outfit and truthfully this was the one I was most frightened of. currently almost done with the pleating then I will need to finish it up with ironing and the zipper, which is the other part I am nervous of, but this was amazingly useful so thank you.

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