What is a hem, and how are hems classified?
A hem is the finished edge at the bottom of a garment or a sleeve. The raw edge is turned under, bound, or faced, then secured, so it will not fray and the garment hangs at the right length. Hems are classified by how the edge is finished and by the stitch that holds it.
A hem is not a seam. A seam joins two panels; a hem finishes a single edge. The two use different stitches and sit in different places, though a bound finish can appear on both.
The hem is more than a finish. It sets the garment's length and silhouette, it is often the most visible edge, and on cheaper garments it is the first thing to fail. So it is worth choosing deliberately, not defaulting to whatever the machine does easily.
Two things decide a hem: how the edge is turned or covered, and the stitch. This guide takes the types, then the stitches, then the depth, then how to match a hem to the fabric and spec it.
The main hem types
A handful of hem types cover most garments. They differ in how the raw edge is enclosed and how much fabric they use.
- Single-fold hem: the raw edge is finished, often overlocked, then turned up once and stitched. It uses little fabric and suits edges that are already neatened, so it is common on casual and knit garments where a bit of exposed finishing is acceptable.
- Double-fold hem: the edge is turned up twice, enclosing the raw edge inside the fold, then topstitched. Clean, durable, and self-finishing, it is the standard on shirts, jeans, and casualwear, and the first hem most people learn.
- Blind hem: turned up and secured with a stitch that catches only a thread or two of the outside fabric, so it is invisible from the front. The default for tailored trousers, skirts, and dresses, where a visible line would cheapen the look.
- Rolled or narrow hem: a very narrow hem, around 3 to 6 mm, rolled and stitched with a rolled-hem foot or by hand. It suits sheers, scarves, and full, curved hems where a deep fold will not lie flat.
- Bound or Hong Kong hem: the raw edge is wrapped in a bias strip rather than turned. A couture and high-end finish for unlined jackets, skirts, and heavy fabrics, where the inside is on show and a folded hem would be too bulky.
- Faced hem: a separate piece of fabric, cut to the shape of the edge, finishes the hem. Used on curved or shaped hems, and to save fabric on a deep hemline or where the shell fabric is too thick to turn.
- Coverstitch or twin-needle hem: two parallel rows of topstitching over a stretch underside, sewn on a coverstitch machine or with a twin needle. The ready-to-wear standard for knit hems, because it stretches with the fabric.
- Lettuce hem: a knit edge stretched hard as it is zigzagged or overlocked, so it waves like a lettuce leaf. A decorative finish on activewear, dancewear, and jersey, and it only works on a fabric with real stretch.
- Fused or no-sew hem: held with heat-activated hem tape rather than stitching. Quick and thread-free, used for fast fixes and some light garments, though it is less durable than a sewn hem and can fail in a hot wash.
How the stitch makes the hem
The same fold can be secured several ways, and the stitch decides how the hem looks and behaves.
- Blind stitch: catches one or two threads of the outer fabric so nothing shows. Factories use a blind hemmer, a machine that chain-stitches with a bent needle through about one and a half thicknesses of fabric.
- Topstitch: one or two visible rows on the outside, the everyday hem on shirts and casualwear, quick to sew and easy to check. On jeans it is a chainstitch, which shrinks a little in the wash and gives the classic roping effect at the hem.
- Coverstitch and twin needle: two straight rows on the face over a looped, stretchy understitch, so a knit hem gives with the fabric instead of popping. The coverstitch is the factory version; a twin needle mimics it on a home machine.
- Hand stitches: slip, catch, and pick stitches secure a hem by hand for tailoring and couture, nearly invisible and soft, with no machine line.
A heavy fabric with a deep hem sometimes gets a dressmaker's hem, an extra loose row of stitching in the middle of the hem so the weight does not hang from a single line.
Hem depth: the spec number
Hem depth, the amount turned up, is the number a tech pack pins down. It follows the garment and the fabric weight, and it is measured as part of the hem allowance.
- Skirts, dresses, and coats: usually 5 to 7.5 cm (2 to 3 inches), enough weight to hang cleanly.
- Jackets, trousers, and blouses: usually 2.5 to 5 cm (1 to 2 inches).
- Rolled and handkerchief hems: about 6 mm, the narrowest finish.
Heavier fabric takes a shorter hem, since a deep fold in thick cloth adds bulk and weight. A curved hem is kept shallow or faced, because a deep fold cannot follow the curve without puckering. The depth is a deliberate call, not a leftover, and it is one of the first numbers set on the pattern.
Hems, marking, and wear
A hem is also where the garment's length is set and where the edge takes wear, so it earns attention beyond the stitch alone.
- Marking the length: the hemline is marked an even distance from the floor, not from the waist, so it reads level on the body even when the fabric was not cut perfectly straight.
- Letting bias hang: a bias or circular garment is hung for a day or more before hemming, so the fabric drops to its final length and the hem does not dip unevenly later.
- Wear at the edge: a trouser hem drags on the shoe and frays, which is why tailored trousers often carry a strip of hem tape, or kick tape, inside the back of the hem.
- Room to alter: a deep hem leaves fabric to lengthen a garment later, which is why quality trousers and children's wear keep a generous hem allowance.
Matching the hem to the fabric
The fabric decides the hem as much as the garment does. The wrong hem puckers, pops, or hangs badly.
- Knits: a knit needs a hem that stretches, so a coverstitch, a twin needle, or a lettuce edge, never a plain straight stitch that will pop.
- Sheers and lightweight: a rolled or narrow hem, since anything deeper shows through and adds weight.
- Tailored wovens: a blind or hand-stitched hem for an invisible, soft finish.
- Unlined and heavy: a bound or Hong Kong hem, so the inside edge is as clean as the outside.
- Curved and bias: a bias-cut or circular hem should hang before it is cut and hemmed, then be finished narrow or faced so it lies flat.
How to spec a hem in a tech pack
On a tech pack, a hem is a line of decisions, not just a folded edge. A full spec means every garment in the run hangs the same length and the same way.
- Type and depth: single-fold, double-fold, blind, rolled, bound, or coverstitch, and the finished hem depth, which together set most of the look and the labour.
- Stitch and SPI: the stitch type, blind, topstitch, or coverstitch, and the stitches per inch, since a too-loose or too-tight stitch shows on the finished edge.
- Thread and topstitch: thread type and colour, and the number and spacing of any visible topstitch rows.
- Edge finish: how the raw edge is finished, overlocked, bound, or fused, before it is turned, since this decides whether the inside stays clean over time.
It is one more line in the tech pack that runs through textile manufacturing: a type, a depth, and a stitch, held to a tolerance.
How to choose the right hem
Work from the fabric and the look. The fabric sets whether the hem must stretch or stay flat, and the garment sets how visible the hem should be.
- Knit tops and activewear: a coverstitch or twin-needle hem that stretches.
- Sheer and floaty: a rolled or narrow hem, kept light so it does not show through.
- Tailored trousers and dresses: a blind hem, invisible from the front.
- Jeans and casualwear: a double-fold topstitched hem.
- Unlined jackets and couture: a bound or Hong Kong hem, clean on both sides.
Whatever the choice, decide the hem before the sample is cut, since the hem allowance has to be built into the pattern from the start.
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