How to sew a flat-felled seam
The strong, flat seam you see on jeans and shirts: one allowance is trimmed, the other folded over it and stitched down, so there are no raw edges.
Pinny's tip
Practise on a scrap first and decide which side you want the visible double stitching on.
Practise on a scrap first and decide which side you want the visible double stitching on.
What you'll need
- Medium or heavy woven: denim, drill, shirting.
- Jeans needle for denim: heavier needle for the layers.
- Topstitching thread (optional): for a jeans look.
Step by step
- Sew the seam at the full allowance (wrong sides together for stitching on the outside, right sides together for stitching inside).
- Press both allowances to one side.
- Trim one seam allowance narrower than the other so the wider one can wrap over it.
- Fold the wider allowance over the trimmed one, tucking its raw edge under. Press.
- Press the folded allowance flat against the garment and pin.
- Edgestitch close to the fold through all layers.
Watch
Easy How To Sew a TRUE Flat Felled Seam Sewing Tutorial 3 Versions- Step by Step Sewing Tutorial (4:52)
By Notches Sewing · Open on YouTube
The video this technique page has always pointed to, a 4-minute one from Notches Sewing. Embedded from YouTube with credit; we don't host it. It only loads when you press play.
Common mistakes
- Trimming the wrong allowance. Trim the one that ends up underneath.
- Skipping the pressing. The fold is hard to keep even without it.
- Wobbly edgestitching. Use an edgestitch foot or move the needle position.
Watch it done
- Easy How To Sew a TRUE Flat Felled Seam Sewing Tutorial 3 Versions- Step by Step Sewing Tutorial by Notches Sewing on YouTube. Opens on YouTube; the video belongs to its creator.
- How to Sew a Flat Felled Seam aka The Strongest Seam by MadamSew on YouTube. Opens on YouTube; the video belongs to its creator.
- How to Sew a Flat Felled Seam | Sewing Machine by Howcast on YouTube. Opens on YouTube; the video belongs to its creator.
Sources
All checked 1 November 2026. We read these; we did not test the products ourselves.
- Sew Essential: How to Finish Seams - Five Sewing Techniques to Master
- The Sewing Directory: Seam Finishes
- YouTube: Easy How To Sew a TRUE Flat Felled Seam Sewing Tutorial 3 Versions- Step by Step Sewing Tutorial (Notches Sewing)
- YouTube: How to Sew a Flat Felled Seam aka The Strongest Seam (MadamSew)
- YouTube: How to Sew a Flat Felled Seam | Sewing Machine (Howcast)