Sewing a collar onto a jacket requires pinning it in place first, then stitching it down with a needle and thread or a sewing machine, working in stages so the collar sits flat and even.

The process takes about 30 to 45 minutes for a beginner and involves four main steps: preparing the collar and jacket neckline, pinning the collar in the correct position, stitching the undercollar to the jacket, and then stitching the upper collar to finish the edge. The collar must be sewn in two layers—the underside first, then the visible top—so it wraps smoothly around the neck opening without puckering or twisting.

You will need a needle (or sewing machine), thread that matches your jacket, pins, scissors, and a seam ripper if you make a mistake. A jacket collar is one of the most visible seams on a garment, so taking time to pin it correctly before you sew saves you from having to rip out stitches later.

Key Takeaways

  • The undercollar (the side that touches your neck) is sewn to the jacket first, and the upper collar is sewn on top of it to hide the raw edges and stitching.
  • Pin the collar at the center back of the neckline first, then work outward toward each shoulder, checking that the collar sits flat and does not twist.
  • Stitch the undercollar with a running stitch or machine stitch about 1/4 inch from the edge, following the curve of the neckline.
  • Fold the upper collar over the seam, pin it in place, and stitch it down by hand or machine to create a finished edge that looks professional.
  • Press the collar with an iron after sewing to flatten the seams and help it hold its shape.

Prepare the Collar and Jacket Neckline

Before you pin anything, check that your collar pieces are cut correctly and that the jacket neckline is ready to receive them. If you are working from a pattern, you should have two collar pieces: the undercollar (which will be sewn to the jacket first) and the upper collar (which will be sewn on top to finish the edge). The undercollar is usually slightly smaller than the upper collar so it does not show from the outside.

If the collar pieces have interfacing (a stiff backing sewn into the fabric), make sure it is already fused or sewn in place before you begin. Check the jacket neckline for any loose threads or seams that need finishing. If the jacket has a facing (a strip of fabric that finishes the inside of the neckline), it should already be attached. Trim any excess thread and press both the collar pieces and the neckline with an iron so everything lies flat.

Pin the Undercollar to the Jacket Neckline

Lay the jacket flat on your work surface with the inside facing up. Place the undercollar on top of the neckline, with the right side of the collar facing the right side of the jacket. Start by pinning at the center back of the neckline—the middle of the back of the neck—so the collar is centered. Push the pin straight through all layers and find it.

From the center back, work outward toward each shoulder, placing pins about 1 inch apart. As you pin, smooth the collar gently so it follows the curve of the neckline without bunching or twisting. The collar should lie flat against the jacket, not pull away or fold over itself. Pay special attention to the corners where the collar meets the front edges of the jacket—these areas are prone to puckering if the collar is pinned too tightly or at the wrong angle. Once the entire undercollar is pinned, try the jacket on briefly to check that the collar sits evenly around your neck.

Stitch the Undercollar to the Jacket

You can sew this seam by hand with a running stitch or by machine. If you use a machine, set it to a straight stitch with a stitch length of about 2 to 2.5 millimeters. If you sew by hand, use a needle and thread that matches your jacket, and make stitches about 1/8 inch long and 1/4 inch from the edge of the collar.

Start stitching at one shoulder seam and work toward the center back, then return to the other shoulder and stitch to the center back. Stitching in two directions from the shoulders prevents the fabric from shifting as you work. Sew about 1/4 inch from the raw edge of the collar, following the curve of the neckline. Backstitch or lock your thread at the beginning and end so the seam does not unravel. Once the undercollar is sewn all the way around, remove the pins and press the seam flat with an iron.

Fold and Pin the Upper Collar

Turn the jacket right-side out. Fold the upper collar in half lengthwise so the two long edges meet, with the right side of the fabric facing inward. Slide this folded collar over the neckline seam you just stitched, so the raw edges of the upper collar wrap around and cover the stitching and raw edges of the undercollar. The upper collar should sit smoothly over the seam without bunching.

Pin the upper collar in place, starting at the center back and working outward toward the shoulders, just as you did with the undercollar. Make sure the fold of the upper collar runs along the neckline seam so it hides all the stitching. Check that the collar is even on both sides of the neck and that it does not twist. The upper collar should be slightly looser than the undercollar so it wraps around without pulling.

Stitch the Upper Collar and Finish the Edge

Stitch the upper collar down by hand or machine, sewing about 1/4 inch from the folded edge. This stitching should run parallel to the neckline seam and catch all the layers underneath. If you sew by hand, use a ladder stitch (also called an invisible stitch) so the stitches do not show on the outside of the collar. To make a ladder stitch, bring the needle out through the fold of the upper collar, then cross over and go through the jacket fabric just below the seam, then back into the fold of the collar about 1/4 inch away. Repeat this zigzag pattern all the way around the neckline.

If you use a machine, sew from the inside of the jacket so the stitching does not show on the outside. Once the upper collar is sewn all the way around, remove the pins and press the entire collar with an iron. Use a pressing cloth (a thin piece of cotton) between the iron and the collar to avoid scorching the fabric. Press from the inside of the jacket first, then flip it over and press the outside so the collar lies flat and holds its shape.

Check the Collar for Even Fit and Adjust if Needed

Try on the jacket and look in a mirror to check that the collar sits evenly around your neck and does not twist or pull to one side. The collar should frame your neck smoothly and the two front points should meet at the same height. If one side is higher than the other, you may need to adjust the stitching on that side.

If the collar is twisted or bunched, you can use a seam ripper to carefully cut and remove a few stitches, then re-pin and re-stitch that section. Start with just a few inches at a time so you do not have to redo the entire collar. Once the collar sits correctly, press it again and the jacket is ready to wear.

Frequently Asked Questions

What is the difference between the undercollar and upper collar?

The undercollar is sewn to the jacket first and sits against your neck. The upper collar is sewn on top of it to hide the raw edges and stitching. The upper collar is usually slightly larger so it wraps smoothly around the seam without pulling.

Can I sew a collar on by hand, or do I need a sewing machine?

You can sew a collar entirely by hand using a running stitch for the main seams and a ladder stitch to finish the upper collar. A machine is faster and produces more even stitches, but hand sewing works well if you take your time and keep your stitches small and consistent.

What should I do if the collar is puckering or bunching?

Puckering usually means the collar was pinned too tightly or the fabric shifted while you were sewing. Use a seam ripper to remove the stitches in the bunched area, re-pin the collar more loosely, and stitch again. Press with an iron after sewing to help flatten the fabric.

How do I keep the collar from twisting to one side?

Pin the collar at the center back first, then work outward toward each shoulder. Check that the collar follows the curve of the neckline evenly on both sides before you stitch. If it still twists after sewing, you may need to remove a few stitches on one side and re-pin it more carefully.

Do I need to use interfacing in the collar?

Interfacing makes the collar stiffer and helps it hold its shape, which is why most jacket collars have it. If your collar pieces do not already have interfacing, you can fuse it to the undercollar before you sew it to the jacket. Follow the instructions on the interfacing package for the correct heat and pressure.