Attach the collar in two stages: first sew the undercollar to the neckline, then fold and stitch the upper collar by hand

A sewn collar stays in place better than a glued one and gives a finished look to any shirt. The process takes about 30 to 45 minutes once you have the collar piece ready. You will sew the undercollar (the side that touches your neck) to the shirt neckline with a machine, then fold the upper collar over it and hand-stitch it closed from the outside. The hand-stitching is what makes the collar sit flat and look professional.

The key is keeping your seam allowance even—typically 5/8 inch—and pressing as you go. Pressing after each step flattens the seams and makes the next step easier. You will need a sewing machine, thread that matches your shirt, a needle for hand-sewing, pins, scissors, and an iron.

Key Takeaways

  • Pin the undercollar to the neckline with right sides together, matching the center marks, and sew with a 5/8-inch seam allowance.
  • Trim the seam allowance to 1/4 inch after machine-sewing to reduce bulk where the collar meets the shirt.
  • Fold the upper collar over the seam, press it flat, and pin it in place before hand-stitching with a ladder stitch or slip stitch.
  • Press the finished collar from both sides to set the stitches and may support it lies flat against the neckline.

Prepare the collar and shirt neckline

Before you sew, check that both the undercollar and upper collar are cut to the same size and that the neckline of your shirt is finished (edges are not raw). If the neckline is raw, you may want to finish it with a narrow zigzag stitch or bias tape first, though many sewers skip this step on casual shirts.

Mark the center of the neckline on your shirt with a pin or a small chalk mark. Do the same on the undercollar. Also mark the shoulder seams on both the shirt and the collar. These marks help you align the collar evenly so it does not twist. Press the undercollar with an iron to remove any wrinkles, and press the upper collar as well.

Machine-sew the undercollar to the neckline

Place the shirt with the right side facing up. Lay the undercollar on top with its right side facing down (so the two right sides are together). Match the center marks and the shoulder marks, then pin around the entire neckline, spacing pins about 2 inches apart. The undercollar should curve smoothly around the neckline without puckering.

Sew with a 5/8-inch seam allowance, starting at one shoulder seam and ending at the other. Sew slowly around the curves and backstitch at the start and end. After sewing, press the seam flat from the wrong side of the shirt, then trim the seam allowance down to 1/4 inch using scissors or pinking shears. Pinking shears leave a zigzag edge that is less likely to fray. Press the seam again after trimming.

Fold and position the upper collar

Now fold the upper collar down so its right side faces the right side of the shirt. The upper collar should cover the seam you just made. The raw edge of the upper collar should align with the raw edge of the undercollar. Pin the upper collar in place all the way around the neckline, making sure the fold lies flat and the collar does not twist.

Press the upper collar with an iron while it is pinned. This sets the fold and makes hand-stitching easier. Check that the collar sits evenly on both sides of the neckline and that the points (if your collar has points) are symmetrical.

Hand-stitch the upper collar closed

Thread a needle with thread that matches your shirt. Tie a knot at the end. Starting at one end of the collar, use a ladder stitch (also called a slip stitch) to close the upper collar to the undercollar. Bring the needle up through the fold of the upper collar, then slide it across into the undercollar seam, and back out through the fold. Repeat this zigzag motion all the way around the neckline. Keep your stitches small—about 1/8 inch—so they are not visible from the outside.

Work slowly and do not pull the thread too tight, or the collar will pucker. When you reach the end, take two small stitches in the same spot and tie off the thread on the inside. Trim the thread close to the knot.

Press and finish the collar

Once the hand-stitching is complete, press the entire collar from the wrong side (the inside of the shirt) with a warm iron. Then flip the shirt over and press from the right side. This sets all the stitches and flattens the collar against the neckline. Pay special attention to the fold line at the top of the collar and the seam where the collar meets the shirt.

If you see any puckering or uneven spots, gently steam them out with the iron. A well-pressed collar should lie flat and smooth, with no visible hand-stitches from the outside.

Common mistakes and how to avoid them

The most common error is sewing the undercollar with an uneven seam allowance, which causes the collar to twist. Measure your 5/8-inch allowance with a ruler before you start, and check it every few inches as you sew. If you are using a presser foot with a guide, use it to keep the allowance consistent.

Another mistake is not trimming the seam allowance after machine-sewing. Leaving it at 5/8 inch creates a thick, bulky ridge under the upper collar that shows from the outside. Always trim to 1/4 inch. A third error is pulling the hand-stitching too tight, which puckers the collar. Keep the tension loose and let the fabric do the work.

Finally, skipping the pressing steps makes the collar look wrinkled and unprofessional. Press after the machine-sewing, after pinning the upper collar, and again after hand-stitching. The iron is as important as the needle.

Frequently Asked Questions

What stitch should I use if I do not know how to do a ladder stitch?

A backstitch works well and is easier to learn. Bring the needle up through both layers of fabric, go back 1/8 inch, and push the needle down. Come back up 1/8 inch ahead and repeat. The stitches will be visible from the inside, but that is fine since nobody sees the inside of the collar.

Can I machine-sew the upper collar instead of hand-stitching it?

Yes, but it is harder to keep the stitches hidden. If you machine-sew, use a very short stitch length and sew as close to the fold as possible. Most sewers hand-stitch because it gives a cleaner finish and is actually faster once you get the rhythm down.

What if the collar is twisted after I sew it?

Unpick the hand-stitches and the machine-stitches, and start over. Twisting usually means the undercollar was not pinned evenly to the neckline. Take extra time pinning the second time, and check the alignment before you sew.

How do I keep the collar points sharp and crisp?

Press the collar points with the tip of the iron, using a pressing ham or a rolled towel underneath to support the curve. Press from the wrong side first, then the right side. If the points are still soft, a light spray starch before pressing helps them hold their shape.

Do I need to finish the raw edges of the collar with bias tape?

No, it is optional. On casual shirts, most sewers leave the raw edges inside the collar. On formal shirts, some sewers add bias tape to the neckline seam before attaching the undercollar, but this adds time and is not necessary for the collar to function well.