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!

8 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?

  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.

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