Beginner · 5 minutes · 6 steps
How to understitch
Understitching takes two minutes and is the difference between a neckline that stays put and one that flips its facing out every time you move. It is a single line of stitching that never shows on the outside.
Why it's worth learning
Any faced or bound edge — neckline, armhole, waistband, pocket opening — needs understitching. It is the most useful two minutes in garment sewing.
What you'll need
- Iron
- Nothing else
Fabric notes
- Works on every fabric, woven and knit.
- On very thick fabric, trim and grade the seam allowances first so the understitch line lies flat.
The steps, in order
- 01
Sew the facing or binding on as usual
Complete the seam that joins the facing to the garment edge, and clip any tight inner curves so the seam can lie open.
- 02
Trim and grade the seam allowances
Trim both allowances back, cutting the one nearest the garment slightly shorter. Grading removes the ridge that otherwise prints through.
- 03
Press both allowances towards the facing
Everything — facing and both seam allowances — goes to one side, away from the garment.
- 04
Stitch through facing and allowances only
From the right side of the facing, stitch about 2 mm from the seam line, catching the facing and both seam allowances but not the garment.
- 05
Follow curves slowly
Necklines are curved; stop and reposition rather than stretching the fabric to keep it under the needle.
- 06
Press the facing to the inside
Roll the facing to the wrong side and press. The understitching pulls the seam a fraction to the inside, so no facing shows from the front.
Mistakes worth avoiding
Skipping it entirely
The facing or binding rolls out and shows at the neckline within one wearing — the most common giveaway on homemade clothes.
Catching the garment fabric
The stitching then shows on the outside. Keep the garment folded away from the needle as you sew.
Not grading the allowances
A thick unsegmented allowance leaves a visible ridge under the neckline once pressed.
Practise it on a project
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