Hem Allowance Calculator

Double fold is the default for most garments — it encloses the raw edge completely and works for almost any fabric weight. Narrow/baby hem is better for lightweight fabrics where a wider hem would add bulk.

Blind hem is the choice for formal garments where no stitching should be visible from the outside. Faced hem is essential for curved hems (circle skirts, scalloped edges) where a straight fold would distort the shape.

Topstitched is the casual/sporty option — visible stitching that becomes a design element. Rolled serger hem is the fastest and lightest option if you have an overlocker.

The quality of a hem depends more on accurate pressing than on the stitch itself. Every fold should be pressed first — measure, pin, press, then sew. A hem gauge (small metal ruler with a slider) is worth its weight in gold for consistent depth.

For curved hems, ease the curve as you press — use steam and your fingers to shape the fabric smoothly around the curve. Never stretch the fabric when pressing, as this creates waves.

Hem depth is a design choice as much as a technical one — a deeper hem adds weight that helps a garment hang, while a shallow hem keeps a light fabric floating. These are the conventional starting points:

The rule underneath the table: the more a hem curves, the shallower it must be. A folded hem has to absorb the difference in circumference between the cut edge and where it lands, and the deeper the fold, the more excess there is to absorb. That is why a circle skirt gets 1/4 in and a straight skirt can carry 2 in.

Wavy knit hems are a stretching problem, not a stitching problem. The fabric gets pulled as it feeds through the machine and sets in that stretched state. Three things fix it, in order of effect: reduce presser foot pressure, use a walking foot so both layers feed at the same rate, and support the hem with fusible knit stay tape or a strip of lightweight interfacing before folding.

Use a stretch or ballpoint needle so the point pushes between the knit loops instead of piercing them, and a twin needle if you want the two parallel rows that read as ready-to-wear. The zigzag the twin needle forms underneath is what lets the hem stretch without popping stitches.

Do not pull the fabric taut while sewing to keep it flat — that is the cause, not the cure. Let the feed dogs move the fabric and guide it only lightly from behind.

Hang the garment for 24 hours before marking the hem, and longer for a bias-cut or circle skirt — 48 hours is not excessive. Fabric on the bias drops under its own weight, and the amount it drops is uneven around the garment because the grain changes continuously around a curve. Hem it immediately and the hemline will be crooked within a week of wearing.

Mark the hem while wearing the garment with the shoes and undergarments you intend to wear with it, measuring up from the floor rather than down from the waist. Body posture changes what hangs level, and measuring from the floor is the only method that accounts for it.

Trim the excess only after marking. It is the last irreversible step in making a garment, and the one most worth waiting on.