How to Sew a Flat Fell Seam That Looks Professional


Take a look at your jeans or a men’s dress shirt and it’s likely you’ll spot flat fell seams. On the outside of the garment there’s a pair of stitch lines, while the inside is all tidy without any raw seam edges. If you’ve wondered how it’s done, it’s not magic — sewing a flat fell seam is a technique every garment sewer can (and should!) learn.

Flat Fell Seam

Level: Easy

What You Need

  • Fabric
  • Thread
  • Pins
  • Iron
  • Instructions

    1. Pin

    flat fell seams

    Pin the fabric of the seam together, wrong sides facing.

    2. Stitch

    sew seam

    Sew the seam at the project’s allotted seam allowance. (We used ⅝”.)

    3. Press

    press seam

    Press the seam open on both sides of the fabric.

    4. Trim


    Trim one side of the seam allowance down to ¼”. Do not trim the other side.

    5. Fold


    Press the untrimmed seam allowance over the seam and on top of the trimmed side. Fold the pressed side under, tucking the raw edge into the fold.

    press the fold

    Press the fold, making sure the raw edge is fully tucked under and the flap left is the same width along the seam.

    6. Finish

    line up

    Line up your fabric in your machine so the stitching is close to the fold. Stitch along the edge of the fold, trapping all the raw edges inside.

    That’s it! You’ve just finished a neat and tidy flat fell seam.

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    5 Responses to “How to Sew a Flat Fell Seam That Looks Professional”

    1. Mike

      If there is no need for a pattern seam allowance for fit, would it work to line up the two raw edges ¼ “ away from each and sew ½ back? This would eliminate trimming.

    2. Peter Van-Stratten

      Fab finish. Will be giving this a try for sure.

    3. Sonja

      Thanks for sharing. I love the look of this finished seam as it looks professional and gives the garment a high-end feel. I’ve seen this done by hand too.

    4. san diego sews

      It would be more clear if the photos in step 5 were at the same orientation as the other photos.

    5. Srey Sen

      Thank you for sharing it. Was sewing a dress shirt with full on french seams, in arm holes and sides. I found it too thick at the intersections under the arm. So flat felt save the day!!