How do I hem something on a sewing machine?

Hemming goes wrong for two reasons: the maths, and the fold. The maths is that a hem is measured from the finished length downwards, not from the raw edge upwards, so you decide where the garment should end and then add fabric below it. The fold is that a hem needs to enclose its raw edge, which means two turns, not one. Get both right and the technique itself is straightforward.

What you'll need

• An iron — this job is more pressing than sewing
• A ruler or a hem gauge
• Pins or hem clips
• Tailor's chalk or a fabric marker
• A blind hem foot, for the blind hem method

Step by step

1. Establish the finished length while wearing the garment.On trousers, wear the shoes you will wear with them and stand naturally. On a skirt or dress, stand in front of a mirror and have someone pin it. Length judged flat on a table is almost always wrong, because the garment hangs differently on a body.
2. Mark the finished length all the way round.Chalk a line, or pin at intervals of about 10cm. Measure up from the floor rather than down from the waist if the garment must be level, because bodies are not symmetrical.
3. Add the hem allowance below the line and cut.For a straight hem, a depth of about 2 to 4cm plus a 1cm turn-under is typical. Wider looks better on a heavy fabric or a straight skirt; narrower suits light fabric. Measure this down from the marked line at frequent intervals and cut along the new line.
4. Press the small turn-under first.Fold up about 1cm and press it all the way round. On a hem this is easier if you press over a strip of card cut to the width, so every point is identical.
5. Press the main hem fold.Fold up by the hem depth so the first fold is now hidden inside, and press hard. Pin at intervals. The raw edge is now completely enclosed between layers and can never fray into view.
6. Stitch close to the upper folded edge.From the wrong side or the right side depending on which you can see better, running a consistent distance from the fold — about 2mm inside it. This row shows on the right side as a single line of stitching, which is normal and expected on trousers, shirts and casual garments.
7. Use a blind hem instead where no stitching should show.Press the hem as above, then fold the whole garment back on itself so that only a few millimetres of the hem edge project. A blind hem foot and stitch then catch one or two threads of the outer fabric at intervals. Practise on a scrap — the amount of fabric caught is the whole difficulty.
8. Handle a curved hem differently.A flared skirt hem has more fabric at the raw edge than at the fold line, so it will not lie flat. Use a narrow hem — 1cm turned twice — or run a line of long machine stitches near the edge and gently draw up the excess before pressing.
9. Deal with a lining separately.On a lined skirt or dress, hem the lining independently and shorter than the outer fabric — typically 2cm shorter — so it never shows and does not restrict the outer hem. Never hem the two together unless the garment was made that way.
10. Press the finished hem.From the wrong side, with a cloth if the fabric marks. Pressing settles the stitching and is what makes a home-made hem look bought.

Tips

• A twin needle gives two parallel rows on the right side and a zigzag underneath, which is what ready-to-wear jersey hems have. It is the neatest way to hem a t-shirt on an ordinary machine.
• Hem tape and fusible web hold a hem without stitching, and they stiffen the fold and eventually let go in the wash. They are a reasonable temporary answer and not a permanent one.
• On thick fabric, reduce the hem depth. A deep hem in coating fabric makes a rigid band that stops the garment hanging.
• Hang a bias-cut or a very drapey garment for a day or two before hemming, so it can drop before you measure.

Common mistakes

• Measuring the hem up from the raw edge — The raw edge is not necessarily level or the right distance from anything. The finished length is the reference, and everything is measured from it.
• A single fold with a raw edge inside — It frays inside the hem, and eventually the fray reaches the stitching and the hem drops. Two folds, always, on a woven fabric.
• Cutting before pinning and checking — You can always cut more off. Pin the hem up, try the garment on, and only then cut the excess.
• Hemming a flared skirt with a deep hem — The circumference of the raw edge is larger than the fold line, so the excess has to go somewhere and it goes into ripples. Narrow hems on flared shapes.

If it doesn't work

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