To hem a garment, mark the finished length, press the hem allowance to the wrong side, enclose or finish the raw edge, and stitch it in place. Use a double-fold hem for straight or gently curved edges in light and medium woven fabric, a narrow hem for curves and very full skirts such as a circle skirt, and a blind hem when the stitching should be almost invisible from the right side, as on a pencil skirt or trousers.
Below you will find the allowance each hem needs, step-by-step methods for all three, a note on knits and the fixes for hems that go wrong.
Which hem should you use?
The right hem depends on the shape of the edge, the weight of the fabric and how much stitching you want to see.
| Hem | Hem allowance | Best for | What shows on the right side |
|---|---|---|---|
| Double-fold | 2.5 cm (1 in) | Skirts, dresses, tops and trousers in light to medium wovens | One line of stitching |
| Narrow | 1 cm (3/8 in) | Circle skirts, curved shirt tails, ruffles, silky and sheer fabrics | A fine line close to the edge |
| Blind | 3 to 5 cm (1 1/4 to 2 in) | Pencil skirts, trousers, medium and heavy wovens | Tiny dots of thread, nearly invisible |
| Knit, single fold | 2 cm (3/4 in) | T-shirts, sweatshirts, jersey dresses | One or two rows of stretchy stitching |
Check the allowance on your pattern before you choose: 1 cm is too shallow for a blind hem, and 5 cm is too deep to turn smoothly around a curve. Patterns made with Sewly include the hem allowance, 2.5 cm (1 in) on woven fabric and 2 cm (3/4 in) on knits by default, and each sewing guide names the hem that garment uses.
Before you hem: let it hang and mark the length
The hem is sewn last, once every seam that crosses it is sewn, finished and pressed. A few minutes of preparation saves unpicking later.
- Let bias and circle skirts hang. Hang a circle skirt, a bias-cut slip dress or anything with bias sections on a hanger for 24 hours. The bias parts drop and lengthen unevenly; hem too early and the hem dips a week later.
- Try the garment on with the shoes you will wear it with. Have a helper measure up from the floor with a long ruler and mark the length with pins or chalk every 10 cm (4 in) all round. On your own, a chalk hem marker on a stand does the same job.
- Even out the allowance. Lay the garment flat, measure the hem allowance below your marked line all the way round and trim along the new cutting line.
- Reduce bulk at the seams. Inside the hem allowance, press the seam allowances open or trim them to half their width so the folded hem lies flat where it crosses them.
How to sew a double-fold hem
The double-fold hem wraps the raw edge inside two folds, so it needs no other finish. With a 2.5 cm (1 in) allowance:
- Press 1 cm (3/8 in) to the wrong side all round. A seam gauge, or a strip of card notched at 1 cm, keeps the fold even.
- Fold again by 1.5 cm (5/8 in), so the raw edge is tucked into the fold, and press. Pin or clip every 10 cm (4 in).
- Set a stitch length of 2.5 to 3 mm and sew from the wrong side, 1 to 2 mm (1/16 in) from the inner folded edge. Start at a side seam rather than at the center front.
- When you get back to the start, overlap the first stitches by 1 cm (3/8 in) instead of backstitching, then pull the thread ends to the wrong side and knot them.
- Press the hem from the wrong side, then lightly from the right side under a pressing cloth.
Tip: On a flared skirt, the raw edge of the allowance is wider than the skirt at the height where it lands, so the folded hem ripples. Before folding, sew a long stitch (4 mm) 6 mm (1/4 in) from the raw edge and pull the bobbin thread gently to ease in the extra fabric.
How to sew a narrow hem on curves
A narrow hem finishes about 5 mm (3/16 in) wide and turns curved edges without puckers, which is why it is the standard finish on a circle skirt. This machine method needs a 1 cm (3/8 in) allowance and no special foot:
- Press the 1 cm (3/8 in) allowance to the wrong side. On a tight curve, press in short sections and turn the garment as you go.
- Stitch 3 mm (1/8 in) from the fold, through both layers.
- Trim the raw edge close to the stitching, leaving about 2 mm (1/16 in). Small sharp scissors held flat give the cleanest trim.
- Fold the edge over once more, enclosing the trimmed edge, so the first line of stitching is hidden inside the fold.
- Stitch on top of the first line of stitching, or right beside it, then press.
A rolled hem foot makes a similar hem in one pass on lightweight fabric, but it needs practice on scraps and struggles over seams. On a full circle skirt, the two-pass method is more forgiving.
How to sew a blind hem
A blind hem catches only one or two threads of the garment with each stitch, so from the right side you see tiny dots or nothing at all. It needs a deeper allowance of 3 to 5 cm (1 1/4 to 2 in) and suits medium and heavy wovens.
With a sewing machine
- Finish the raw edge with a zigzag or a serger (see finishing seams without a serger), then press the hem allowance up to the wrong side.
- Fold the hem back toward the right side of the garment so that about 5 mm (3/16 in) of the finished edge sticks out beyond the fold. Pin across the fold.
- Fit the blind hem foot and select the blind hem stitch: a few straight stitches followed by one wide zigzag bite.
- Sew with the finished edge under the foot and the fold running along the foot's guide, so the straight stitches land in the allowance and the zigzag barely nicks the fold.
- Open the hem out flat and press. If the bites show too much, move the guide so it catches less of the fold.
By hand
Press the hem up and pin it. Work a slip stitch or a catch stitch: pick up one or two threads of the garment, then slide the needle about 1 cm (3/8 in) along inside the fold or under the edge of the allowance. Keep the thread relaxed, because tight hand stitches dimple the fabric. It is slower than the machine, but it gives the neatest finish on wool and silk.
What about hems on knit fabric?
Knits do not fray, so a single fold is enough. Press up 2 cm (3/4 in) and stitch with a twin needle, a narrow zigzag or your machine's stretch stitch so the hem can stretch with the fabric; a plain straight stitch snaps the first time you pull the garment over your head. Stabilizing a hem that waves is covered in sewing knit fabrics on a regular machine.
Common hem mistakes and how to fix them
| Problem | Likely cause | Fix |
|---|---|---|
| The hem is wavy or flares out | Fabric stretched under the presser foot, often on bias edges and knits | Lengthen the stitch to 3 mm, lighten the presser foot pressure or use a walking foot, then steam the hem to shrink it back |
| One side is longer | Length measured from the waist instead of the floor | Mark again from the floor while wearing the garment and re-hem the long part |
| Puckers along a curved hem | Allowance too deep for the curve | Trim the allowance to 1 cm (3/8 in) and sew a narrow hem, or ease the fullness with a long stitch |
| Blind hem stitches show | The zigzag bites too far into the fold | Adjust the guide so the bite catches one or two threads, and match the thread to the garment fabric |
| Lumps where seams cross the hem | Seam allowances folded up thick inside the hem | Press them open or trim them to half width inside the hem allowance |
| The stitching wanders off the fold | Sewing from the right side without seeing the fold | Sew from the wrong side, watching the inner fold, or use an edgestitch foot as a guide |
Press as you go
Pressing is half of a good hem. Press each fold before you stitch it, press the finished hem with steam, and lift and lower the iron instead of sliding it, which stretches the edge. Use a pressing cloth on dark fabrics, wool and synthetics to avoid shine.