The Basic Process for Attaching a Collar
Sewing a collar to a shirt involves stitching the collar pieces together first, then attaching that finished collar to the neckline of the shirt body. The collar sits between two layers of fabric at the neck — the shirt itself and a facing (a strip of fabric that reinforces the neckline from the inside). You stitch through all these layers at once, which holds everything in place permanently.
The order matters: you prepare the collar, attach it to the shirt front and back, then fold the facing over it and stitch it down. This creates a clean, professional finish on both the outside and inside of the neckline. The whole process takes about 30 to 45 minutes once you have cut and prepared all the pieces.
Key Takeaways
- A collar is sewn between the shirt body and a facing strip, with stitching that goes through all layers at the neckline seam.
- You must interface (add stabilizing fabric to) the collar pieces before sewing them together, or the collar will be floppy and won't hold its shape.
- The collar attaches to the shirt in one continuous seam around the entire neckline, not in separate pieces.
- Pressing with an iron at each step — after stitching the collar together, after attaching it, and after the facing is sewn down — makes the difference between a collar that looks handmade and one that looks professional.
- Clipping into the seam allowance at curves lets the fabric lie flat when you turn the collar right-side out and fold the facing over.
Prepare the Collar Pieces with Interfacing
Before you sew anything, you need to stabilize the collar with interfacing — a layer of stiff fabric fused to the wrong side of the collar. This keeps the collar from drooping and gives it structure. Cut two pieces of interfacing to match your collar pattern pieces (usually one for the top collar and one for the undercollar). Follow the package directions on your interfacing to fuse it to the wrong side of each collar piece using a hot iron.
Once the interfacing is fused, lay the two collar pieces right sides together (the pretty sides facing each other). Pin around the outer edges, leaving the neckline edge (the edge that will attach to the shirt) unpinned. Stitch around the three sides using a 5/8-inch seam allowance — the standard seam width for garment sewing. Leave the neckline edge completely open.
Trim the seam allowance down to 1/4 inch on all three sides you just stitched. At the corners and curves, clip into the seam allowance with small scissors — cut almost to the stitching line but not through it. These clips let the fabric spread when you turn the collar right-side out, so the edges lie flat instead of bunching. Turn the collar right-side out through the open neckline edge, poke out the corners with a point turner or closed scissors, and press flat with an iron.
Attach the Collar to the Shirt Neckline
Lay your shirt flat with the front and back pieces sewn together at the shoulders. The neckline should be open and ready. Pin the collar to the neckline with the undercollar (the side that was against the interfacing) facing the right side of the shirt. The raw neckline edge of the collar should line up exactly with the raw neckline edge of the shirt. Pin all the way around, easing the collar to fit the curve of the neckline.
Stitch the collar to the shirt using a 5/8-inch seam allowance, sewing all the way around the neckline in one continuous seam. Backstitch at the beginning and end to lock the thread. Press this seam flat with an iron, then press it open (fold the seam allowance to one side and press it there). This reduces bulk before you add the facing.
Trim the seam allowance to 1/4 inch. Clip into the seam allowance at the curves of the neckline — these clips let the seam lie flat when you fold the facing over. Do not clip all the way to the stitching; stop just short of it.
Attach the Facing to Finish the Inside
The facing is a strip of fabric cut to the same shape as the neckline. It covers the raw edges and seams on the inside of the shirt. Pin the facing to the neckline with right sides together (the pretty side of the facing against the pretty side of the shirt). The facing should cover the collar seam you just made. Stitch around the entire neckline using a 5/8-inch seam allowance.
Trim this seam allowance to 1/4 inch and clip at the curves just as you did before. Press the seam flat, then press it open. Turn the facing to the inside of the shirt by pulling it through the neckline opening. Press the neckline edge flat with an iron so the facing sits smoothly against the inside of the shirt.
Fold the raw edge of the facing under by about 1/2 inch and pin it to the inside of the shirt, just covering the seam you made when you attached the collar. Stitch this edge down by hand using a ladder stitch (a nearly invisible stitch that runs inside the fold of fabric), or use a machine stitch 1/8 inch from the folded edge. Press the entire neckline one final time with an iron.
Press and Finish the Collar
Pressing is what separates a homemade-looking collar from a professional one. After you attach the collar to the shirt, press the neckline seam flat. After you attach the facing, press the entire neckline again, making sure the collar stands up at the angle you want it to. Use a pressing ham (a curved cushion made for pressing curved seams) if you have one, or fold a towel into a curve and press over that.
If your collar is meant to roll or fold in a particular way — for example, if it is a pointed collar that should stand up — shape it by hand while it is still warm from the iron and let it cool in that position. This sets the shape into the fabric. Once the collar is cool, it will hold that shape.
Troubleshooting Common Collar Problems
If your collar is puckering or bunching at the neckline, you likely did not clip the seam allowance enough at the curves. The fabric needs room to spread so it can lie flat. Unpick the facing stitches, clip more deeply into the seam allowance (still stopping short of the stitching), and re-stitch the facing. Press again.
If the collar is floppy or won't hold its shape, the interfacing may not be fused securely or you may not have used enough interfacing. Check that the interfacing is actually bonded to the fabric by tugging on it — it should not peel away. If it does, re-fuse it with a hot iron and damp pressing cloth. If the collar still droops, you can add a second layer of interfacing to the undercollar.
If the facing is showing on the outside of the shirt at the neckline, the facing is too wide or the seam allowance was too large. On your next shirt, trim the facing narrower before you attach it, or use a smaller seam allowance (try 1/2 inch instead of 5/8 inch) when you stitch the facing to the neckline.
Frequently Asked Questions
Can I sew a collar on by hand instead of with a machine?
Yes, but it takes much longer — usually two to three hours instead of 30 to 45 minutes. Use a backstitch for the main seams (the collar to the shirt and the facing to the neckline) because it is strong enough to hold up to wear. A backstitch is slower than a machine stitch but creates a seam that will not come apart.
What is the difference between a collar and a facing?
A collar is a separate piece of fabric that frames the neckline and is visible from the outside. A facing is a strip of fabric that reinforces the neckline from the inside and is hidden when you wear the shirt. They work together: the collar sits between the shirt and the facing, held in place by the stitches that attach the facing.
Do I need to interface the facing too?
Usually not. The facing is typically a single layer of fabric that does not need to hold a shape the way the collar does. However, if your facing fabric is very thin or stretchy, you can interface it lightly to prevent it from rolling or curling inside the shirt.
What happens if I sew the collar on upside down?
The collar will be backwards — the undercollar (the side that should be hidden) will show on the outside. You will need to unpick the stitches, flip the collar over, and re-stitch it. This is why pinning carefully before you stitch is worth the extra minute.
Can I attach a collar to a shirt that is already finished?
Not easily. A collar needs to be sewn into the neckline seam before the facing is attached, so the three layers (shirt, collar, and facing) are stitched together at once. If the shirt is already finished, you would have to unpick the facing, remove the old neckline binding, and start over. It is much simpler to attach the collar during the initial construction.