What are knife pleats?
A knife pleat is a piece of fabric folded sideways along the fabric length. Knife pleats are a series of multiple such pleats folded into one direction: to the right or left (see the images below). They add fullness to a garment or part of a garment. You can use them to make a pleated skirt or simply as decoration for different clothing – for example skirt or dress hems, or sleeve cuffs. Creating these pleats is not hard at all, however, may be a long process for large projects.
This page contains a knife pleats calculator . It computes the fabric consumption based on the required knife pleat dimensions.
In this tutorial you will learn the following:
- Tools you need to make pleats
- Suitable fabric and fabric preparation
- Formula to calculate fabric consumption
- Knife pleats fabric consumption calculator
- Sewing knife pleats
Tools you need to make pleats
- Ruler (I use a quilting ruler)
- Textile marker
- Fine pins
- Fine needle and thread (optional)
Suitable fabric and fabric preparation
The best choice for making this type of pleats is to use medium to lightweight 100% cotton.
Use 100% cotton fabric for making knife pleats.
In the images below, you can see a 100% cotton pleated skirt I started to sew while writing this tutorial (I still have to finish it :)).
Prepare the fabric for sewing by washing, drying, and pressing it.
Do not finish the seam allowance of the knife pleats where they are going to be sewn to another pattern piece. You would add too much bulk to the folds (see the images below). If your fabric frays badly, finish the raw edge AFTER you have made the pleats. As you can see, the waist of the skirt below has no seam finish either.
Finish the hem it BEFORE pressing the pleats completely. The phase of doing so might be slightly different depending on the project you are working on. However, adding a hem after pressing the knife pleats might result in a visually unappealing design.
Hem the fabric before pressing the knife pleats completely.
Formula to calculate fabric consumption
Consider the visible width and depth of the individual pleats before cutting the fabric. By visible width, I mean the part of the knife pleat that is not hidden below the fold. By pleat depth, I mean how deep you fold the fabric (see the schemes below).
Calculate fabric consumption of knife pleats according to the following formula:
fabric width = number of knife pleats ⨯ (visible width + 2 ⨯ pleat depth)
fabric length = pleat length
Do not forget to add seam allowances and hem allowances before cutting the fabric.
Fabric consumption calculator
Calculated fabric consumption for knife pleats
Do not forget to add seam allowances and hem allowances before cutting fabric.
Sewing knife pleats
1. Choose the direction of folds and mark the seam-allowance
If you decided to fold the knife pleats towards the right-hand side, mark the seam allowance on the right edge of your fabric. On the other hand, if you decided to to fold towards the left-hand side, mark the seam allowance on the left edge.
In this tutorial, I’m going to fold the pleas to the right and mark the seam allowance on the corresponding fabric edge (see the image below).
2. Draw pairs of markings
Using a quilting ruler and textile marker, draw pairs of markings on the RIGHT SIDE of the prepared fabric (see the images below).
Make sure your textile marker can be easily removed from the fabric you use to draw knife pleat fold lines.
3. Connect the markings and create vertical lines
By connecting the markings you draw vertical lines that will indicate the fold lines of the knife pleat and also a line, towards which the knife edge should be moved (see the images below).
4. Fold and pin the lines
Pinch the first knife pleat line (the one not indicating the seam allowance, but the fold) and move it to the right (see the images below). By doing so you create the first fold.
Use pins to keep the folded fabric in place (see the image below). Pin the knife pleats at the top. You can also use multiple pins along the folds to secure the fabric. If you decide to use multiple pins along the folds, make sure they don’t leave big, visible holes in the fabric.
Continue pinching, moving and folding the fabric until you reach the other end of the fabric. The result should look something like this (see the image below).
For large projects like a long pleated skirt, you can also baste the folds into place. To do so, use a fine needle and thread. Again, make sure the needle and thread don’t leave noticable holes.
Pressing the pleats
Before you start pressing the folds, make sure you align the lines you have drawn accurately and the folds are straight (see the image below). If you basted the fabric, the lines are already aligned.
You may press one or even multiple folds at once. This depends on the pleat depth and width you have decided to use for your project. Make sure you do not press the pins.
Sew the top of the knife pleats
Now that you have pressed the pleats, you can sew the top to fix them into position.
You can use the stitching as basting and remove it after you have sewn the pleats to another pattern piece.
At this phase, you can finish the seam allowances at the knife pleats top as well if necessary. Use an overlock machine or a standard sewing machine to do so and continue with your project.