How to Understitch

In this article, you will learn what understitching is and why it is important; two simple rules of understitching; and how to understitch a garment like a boss!

I like to think of understitching as the best friend of topstitching and the first cousin to edgestitching! In fact, understitching is an edgestitch that is close to a seam.

And while topstitching and edgestitching can have a dual personality — functional and/or decorative, understitching is ONE thing:


With understitching, the seam allowances (SAs) of enclosed seams are graded and then stitched to the facing. This gives a nice firm edge for you to turn and press facings to the wrong side (WS).

And it helps facings “know” their place, which is INSIDE a garment.

So if you’re ready, let’s begin with the…

Rules of Understitching

Rule #1: If you’re finishing an edge with a shaped or bias facings or applying a collar, then you cannot, must not skip understitching!

Rule #2: Prior to attaching a shaped facing, it is interfaced for added stability!

Now, here’s…

How to Understitch

It’s really not difficult, but you do have to take your time, so you can be precise!

And here’s how you do it…

Step 1:  Staystitch the neckline and armholes of the garment and the shaped facing. In the image below, I marked the curve for staystitching…

How to Understitch

Step 2: Then, align the right side (RS) of the facing to the RS of the garment’s edge and stitch them together.

Step 3: Now, grade and clip SAs as needed before understitching.

How to Understitch

Did you notice that it is the SA of the facing that is graded in half?

Step 4: Press the SA up towards the facing from the RS of the garment.

How to Understitch

Step 5: Then, from the RS, edgestitch the SAs to the facing. You want to position your needle very close to the seam, no more than ⅛ inch away. I like to find a spot on my presser foot to use as a guide to help me maintain the proper distance away from the seam line!

How to Understitch

Take your time understitching, please!

Once you’ve completed understitching, this is how it looks closeup…

Step 6: Press the facing to the inside of your garment, rolling the RS of the garment ever so slightly towards the inside of the garment. This will be easier because of understitching!

And you’re done! Behold the finished result from the wrong side (WS or the shaped facing side in the featured image at the top of the article.

and now from right side (RS)…

How to Understitch

If you’ve done this right, your facing will hopefully have the good manners to know its place, which is INSIDE the garment!

The End

Along with the staystitch, the topstitch, and the edgestitch, you need to know when to, the value of, and how to understitch!

So remember this:

When applying shaped facings, you must, you must understitch. Because it is the only way to show them who’s the boss!

Plus, it is the only way to end up with a professional end result. Click HERE to see understitching in action!

And remember…

Life is the ultimate red carpet event. Dress for it!

RELATED: Click HERE if you’re ready to unleash your dressmaking superpowers and learn how to sew a simple dress! Warning: This is a MEGA 5-part series!