Tips & tricks

Sewing trouser legs together: put one leg inside the other

The crotch seam is a curve and the trickiest seam on trousers. With this trick you sew it in one go, without twisted legs.

The turned leg is pushed from above into the leg that is still wrong side out

For trousers like Hanne you first sew each leg on its own. Then you join both legs with the crotch seam: at the front from the waist through the crotch to the waist at the back. This seam is a curve, and that's exactly where the typical mistakes happen. One leg gets sewn on twisted, the inseams don't meet, or the seam goes wavy in the curve.

With the inside-out trick almost nothing can go wrong: the legs automatically lie the right way round on top of each other, and you sew the whole curve in one go.

What you need

Your cut trouser pieces with all markings
Pins or fabric clips
For jersey: a jersey needle and a stretch stitch

Step 1

Close each leg on its own

Two separate trouser legs laid flat, each with its inseam sewn

For one leg, place the front and back trouser pieces right sides together and sew the side seam and the inseam. Do the same with the second leg. Now you have two separate tubes.

Check beforehand which piece is the front and which the back: the back piece is longer and more curved at the crotch.

Step 2

Turn one leg, not the other

Left: a trouser leg turned right side out, right: one wrong side out with the seam allowances outside

Turn one leg right side out so the nice side of the fabric is on the outside. The other leg stays wrong side out, with the seam allowances on the outside.

Step 3

Put one leg inside the other

Put the turned leg (right side out) inside the leg that is still wrong side out. Push it in until the edges of the crotch curve lie exactly on top of each other.

Now the two fabrics are automatically right sides together: centre front on centre front, centre back on centre back. The two waist edges are level at the top, and the legs disappear inside each other.

Step 4

Pin the inseams first

Close-up of the crotch curve: pins at the inseam, at the centres and in between, seam allowances in opposite directions

Start in the middle of the curve: place the two inseams exactly on top of each other. Fold the seam allowances in opposite directions so they lie flat and meet neatly. Pin there.

Then centre front and centre back at the waist, then the markings in between. Finally the rest of the curve.

Step 5

Sew the curve in one go

The seam runs through the whole curve in one go, a second time at the bottom, the presser foot is in the curve

Sew from the front waist over the crotch to the back waist without stopping. Slow down in the curve: if the fabric has shifted, leave the needle down in the fabric, lift the presser foot, straighten the fabric, lower the foot and keep sewing. How that works is explained in Sewing straight, even on narrow sleeve hems.

Don't pull on the fabric. Especially with jersey, a curve stretches and goes wavy otherwise, see 5 jersey traps.

Step 6

Seam allowance in the curve, then unpack

Left: seam allowance clipped in the curve, right: the finished trousers with the seams meeting at the crotch

With woven fabric, clip the seam allowance a few times in the lower curve or trim it to about 0.5 cm without cutting into the seam. Then it lies flat without tension. With jersey that isn't necessary: finish the seam allowances together.

Now pull out the inner leg and turn the whole pair of trousers right side out. Look at the crotch from the outside: do the four seams meet as a neat cross?