How to Hem Jeans and Keep the Original Hem

Jeans do not hem like other trousers. A factory hem was sewn on an industrial chainstitch machine in thread far thicker than anything in your box, and then the garment was washed, sanded or stone-treated — which is why the folded edge came out paler than the leg above it. That fade line and the gold stitching are what a stranger's eye reads as these jeans came this way. Cut them off and you get a hem that is technically correct and unmistakably an alteration.

So the denim question is not really how do I hem — that general answer, machine hem and hand blind hem and hem tape, lives in how to hem pants. It is which of two jobs you are doing: keeping the original hem and hiding a tuck above it, or cutting the leg and rebuilding a hem that at least reads as denim. Both are straight lines on a flat edge. This is Level 1 of The Pattern, Threader — the difficulty is not the sewing, it is the setup.

What you need: a jeans needle, matching thread, a seam ripper, pins, chalk or a removable marker, a tape measure, an iron, and something to level the presser foot over the side seams.

Set the machine up first — this is where denim hems actually fail

Almost every "my machine can't handle denim" story is a needle story, and the rest is a presser-foot story.

The needle

Use a jeans/denim needle, not the universal one already in the machine. SCHMETZ builds it with a medium ball point on a reinforced blade, so it punches thick wovens with less deflection — and deflection is what causes both the skipped stitches and the snapped needle that scare people off denim for a year.

Take 90/14 for mid-weight or stretch denim, 100/16 for rigid denim or anywhere you go through a folded hem and a side seam at once, and 110/18 for heavy raw denim. SINGER's own hemming-jeans guide is blunter: a denim needle in at least a size 16, possibly an 18. Put a fresh one in, and keep a pack of machine needles with a couple of denim sizes in it.

For visible gold topstitching the other candidate is a Topstitch needle, which SCHMETZ gives an extra-sharp point and an enlarged groove for large-diameter thread.

The thread

Two separate decisions, and people conflate them.

Thread that must disappear — the tuck in Method 1 — is ordinary all-purpose polyester in a blue matching the leg. Singer specifies all-purpose in needle and bobbin for that method, precisely because nothing is being topstitched.

Thread that must be seen — the visible hem in Method 2 — is topstitching or jeans thread. Gütermann's Denim thread is a No. 50 polyester and its own spec asks for a jeans needle in NM 90 to 110. Keep all-purpose in the bobbin even then; heavy thread top and bottom is how tension goes sideways.

The foot and the settings

• Free arm. Take the accessory tray off so the leg becomes a tube around the machine arm. Both Singer methods start here.
• Stitch length long-ish, 3 to 3.5 mm. Short stitches perforate denim and look fussy beside factory topstitching, which is long.
• Reduce presser-foot pressure if your machine has the dial. Thick fabric wants less.
• A walking foot is optional, but it removes the layer creep that leaves the second leg short — see walking feet. An edge-stitch or bi-level foot from the presser feet box holds an even topstitching line.

Gear mentioned above

What we'd buy for this

One pick per category, chosen from the research pages linked in this piece. Borrow before you buy — nothing here is required to start.

• 
  Seam Rippers

  ZMAAGG$4.99★ 4.8 out of 5 stars · 250 ratings

  Priced in the lower half of this category.

  Why this oneBuy on Amazon
• 
  Machine Needles

  SCHMETZ (130/705$7.45★ 4.8 out of 5 stars · 709 ratings

  Priced in the lower half of this category; universal points, the default for ordinary woven fabric.

  Why this oneBuy on Amazon
• 
  Thread

  Coats & Clark 100%…$12.99★ 4.8 out of 5 stars · 1,753 ratings

  Priced in the lower half of this category; all-purpose polyester, which covers nearly everything a beginner sews.

  Why this oneBuy on Amazon

Researched from listings, specs and owner feedback — never hands-on testing. We may earn a commission; it never changes a pick.

Measure once, with the shoes on

Put on the shoes you will actually wear with these jeans, stand normally, and fold the excess up on the outside of one leg until the hem sits where you want it — on most jeans, just kissing the top of the shoe. Pin, walk a few steps, sit down, look again. Then take them off and measure the fold. That number is the amount removed, and it is the only one you need. Transfer it to the second leg by measurement, never by re-pinning on your body: you will get a different answer and two different legs.

Method 1: keep the original hem

Sometimes called the euro hem. You are not hemming at all — you fold a tuck into the leg and stitch it, leaving the factory hem hanging underneath as the bottom of the jeans.

1. Work on the outside of the leg, jeans right side out. Get this wrong and the tuck ends up inside, where it will not press flat.
2. Fold the leg up so the original hem sits half the amount removed above where you want the new hem to land. Half, because a fold doubles. Singer describes the same geometry from the other end: measure the depth of the distressed band, double it, mark that line, and line the bottom edge of the original hem up with it.
3. Pin every couple of inches, checking the original stitching line stays parallel all the way round and the leg has not twisted on itself.
4. Sew a straight line immediately above the original hem's topstitching, through both layers, in matching all-purpose thread. Close is the whole trick — a millimetre or two above the factory stitch and your line hides in it.
5. Trim the excess inside to about half an inch and zigzag or overedge the raw edge so it does not fray in the wash.
6. Press the tuck upward, towards the knee, and the original hem back down flat.

The factory hem is the bottom of the jeans again — fade line intact, gold stitching intact, a small ridge hidden inside the leg. Alterations shops charge more for this than for a plain hem, which tells you how the two compare.

The bump at the side seam

Where the flat-felled outseam crosses your stitching line there are suddenly six or eight layers, the foot tips nose-up, the feed dogs lose grip, and the machine skips stitches or jams. It is a geometry problem, not a power problem.

• Level the foot. A hump jumper (also sold as a Jean-a-ma-jig) is a small stepped shim you slide under the back of the foot approaching the seam, then under the front coming off it. A folded scrap of the same denim, or a folded index card, does the same for nothing.
• Use the button, if your foot has one. On Brother machines the zigzag foot has a locking pin — the black button on its left side — and Brother's own thick-fabric guidance is to press it so the presser foot stays level while sewing. The same page offers the paper-under-the-heel trick as the alternative.
• Hand-wheel across it. Stop short of the bump and turn the handwheel towards you, stitch by stitch, before resuming the pedal.
• Flatten it first. A firm press with a steam iron compresses the layers; the r/sewing regulars go further and hammer the seam with a mallet through a scrap of cloth — the same reason factory hems are pounded flat.
• Know the ceiling. That Brother page warns that above roughly 6 mm of fabric, or if you push it through, the needle may bend or break. A folded denim hem crossing a flat-felled seam sits right at that edge, which is why level and slow beat a bigger motor.

When the original hem trick does not work: tapered legs

The tuck assumes the leg is about as wide where the hem is going as where it came from. On a straight leg it is. On a tapered or flared leg it is not: you are folding a wider circle against a narrower one, or the reverse, and you get puckering, a ripple, or a small bell. The consensus in r/sewing is consistent — keep the original hem on straight legs and expect the trick to fight you otherwise. Limits worth knowing:

• Under about an inch and a half on a mild taper, the fabric eases in and presses flat if you distribute the fullness rather than letting it pool at the seams.
• Three inches or more, or a genuinely skinny taper: cut and rebuild. The bulk inside the leg stops being invisible around there anyway.
• Any flare — the folded hem is wider than the leg it lands on, with nowhere for the excess to go.

Method 2: cut and rebuild the hem

When the original hem is beyond saving — frayed through, or the leg is tapered — build a new double-fold hem. It will not have the fade line, and nothing done at home will: that pattern is the residue of an industrial wash on a finished garment. Matching gold topstitching gets you most of the way.

1. Mark the finished length, then mark a cut line one inch below it, parallel to the existing hem, all the way round — Singer's guide leaves exactly that allowance.
2. Cut on the line, checking both legs match before you cut the second.
3. Fold up half an inch and press. Fold up half an inch again, enclosing the raw edge, and press again. A double half-inch fold is the right depth for denim, which gets thick fast.
4. Topstitch from the inside leg seam so start and finish meet somewhere inconspicuous, holding an even distance from the folded edge.
5. Backstitch, trim the tails, press.

To practise the fold-and-press rhythm at lower stakes first, fix a fallen hem is the same movement on one short section.

Denim is made by the iron

A hem is made by the iron and merely secured by the thread, and that is truer of denim than of anything else — cotton denim takes heat and steam happily and holds the crease.

• Press the original fold flat and open before you measure, or the old crease shadows through the new hem. Press each fold as you make it, not all at the end.
• Steam generously, and press means lift and set down. Sliding the iron along stretches the folded edge into a wave.
• A heavy iron does this for you; a light one makes you push, which is the wrong motion. See irons for what matters in one.

What it will honestly look like

Method 1, done carefully, is very hard to spot — the factory hem is genuinely still there, and the only tell is a slight thickness if somebody handles the cuff. Method 2 reads as a good hem in matching thread, and improves over three or four washes as the new fold wears.

Either way the first leg comes out wonkier than the second, and you will notice a wandering seam nobody else ever will. Wear them. Wonky seams are the whole point.