Fabrics and care · 8 October 2026 · 3 min read

How to mend a split seam by hand

How to fix a ripped seam by hand with a backstitch, step by step, and how to tell a split seam from torn fabric or a fit that is too tight at the underarm.

Inspiration

The quick answer

Turn the garment inside out, start sewing a little way before the gap on the original stitching line, and backstitch along that line to a little way past the gap, with small even stitches in matching thread. A backstitch is the strongest hand stitch for a seam and, done neatly, it is invisible from the outside.

First, though, make sure it really is the seam that has split.

Split seam, torn cloth or tight fit?

Look closely at the gap from the inside. What you find decides whether a simple hand repair will last:

A split seam: the stitching thread has broken, but both fabric edges are whole and you can still see the old needle holes. This is the easy one.
Fabric pulling away: the seam stitching is intact, but threads of the fabric have slipped or frayed beside it, leaving a ladder of loose threads. A deeper seam is needed, which makes the garment slightly smaller.
Torn fabric: the cloth itself has ripped next to or across the seam. That is a mend rather than a seam repair; see a small hole or tear in lawn.
A fit that is too tight: the same seam splits again and again, usually at the underarm, across the seat or at the side slits. Restitching will not stop it; the garment needs more room.

Backstitching the seam, step by step

You need a hand-sewing needle, thread close to the fabric colour, a few pins and small scissors. Polyester all-purpose thread is strong and suits most fabrics.

Turn the garment inside out and pin the two edges together along the old stitching line.
Knot the end of a single length of thread, about the length of your arm.
Start in the intact stitching, about 1.5 cm (just over half an inch) before the gap, so the repair is anchored.
Bring the needle up one stitch length ahead, then take it back down at the end of the previous stitch. Repeat, so the stitches touch on the outside.
Keep each stitch about 2 or 3 mm long and follow the old needle holes where you can.
Carry on about 1.5 cm into the intact stitching on the far side, make two or three tiny stitches on the spot, and knot.
Trim the thread and press the seam flat from the inside.

Underarms, curves and frayed edges

The underarm is the most common split because it is curved and takes strain every time you lift your arm. Use slightly smaller stitches there and do not pull the thread tight, as the seam needs a little give. Where the sleeve seam meets the side seam, add a few extra stitches over the crossing point.

If the raw edges of the seam allowance are fraying, finish them after the repair with a whipstitch: small diagonal stitches over the edge, so the fraying cannot creep back into the seam.

When a seam keeps splitting

A seam that opens repeatedly in the same place is telling you about the fit, not the thread. Tight armholes are a common cause; armhole and shoulder fit problems explains how they arise, and letting out a kameez covers how much room an existing seam may have. We do not alter existing clothes, so any of this is work for you or a tailor near you.

For a new outfit, the measurements and how loose you want it are agreed in writing before cutting. Custom stitching explains how it works, and you can start a quote with your measurements and a note about where garments usually feel tight.

Common questions

Can I use a running stitch instead of a backstitch?

On a seam that takes little strain, such as a dupatta edge, a small running stitch may do. For side seams, underarms and trousers, a backstitch is much stronger and less likely to open again.

What if the seam allowance has frayed right back?

Then there is not enough fabric for the original seam. You can sew a new seam slightly further in, which makes that part a little narrower, or take the garment to a tailor near you if it is already snug.

How do I hide the knot?

Start and finish on the inside, in the seam allowance. A couple of tiny stitches on the spot before the final knot keeps the thread from working loose, and the knot stays out of sight.

More guides