Hemming jeans on a sewing machine takes about 30 minutes once you measure and pin
A sewing machine hem on jeans is stronger than hand-stitching and lasts through many washes. The basic process is: try on the jeans, mark where you want them to end, fold and pin the hem, and sew a straight line around the leg. The hardest part is usually getting the fold even, not the sewing itself.
Jeans are thicker than most fabrics because of the weight of the denim and the existing seams at the inseam and outseam. Your machine needs to be threaded correctly and set to a straight stitch with medium tension. If your machine struggles or skips stitches when you hit a thick seam, you may need a heavier needle — a size 16/100 or 18/110 works better on denim than the standard 14/90.
Key Takeaways
- Wear the jeans with the shoes you will wear them with, then have someone mark the length with chalk or a fabric pen while you stand still.
- Fold the hem up inside the leg, pin it flat every inch or so, and try the jeans on again to confirm the length before you sew.
- Use a straight stitch, sew slowly when you cross the inseam or outseam, and backstitch at the start and end to lock the thread.
- A size 16/100 needle handles denim better than a standard needle, and you can find them at any fabric store or online.
Measure and mark the hem length while wearing the jeans
Put on the jeans with the shoes or socks you plan to wear with them. Stand on a flat floor and have someone mark the length with tailor's chalk, a fabric pen, or a regular pencil on the inside of each leg. Mark where the hem should end — usually about half an inch above your shoe. Mark both legs at roughly the same height by having your helper use a ruler or measuring tape held level.
If you are hemming alone, stand in front of a mirror and mark with chalk or pen, then check that both marks are at the same distance from the floor. It does not have to be perfect — a quarter-inch difference is invisible when you wear them.
Fold, pin, and try on the jeans before sewing
Take off the jeans and lay one leg flat on your ironing board or table. Fold the hem up along your chalk line, so the inside of the leg is now facing out. The fold should be crisp and straight. Pin the fold every inch or so with straight pins, pushing them through both layers of fabric. Do the same for the other leg.
Put the jeans back on and look in the mirror. Walk around for a few seconds. If the length looks right, take them off and lay them flat again. If the hem is too short or too long, unpin one leg, adjust the fold, and try on again. Once both legs look correct, you are ready to sew.
Thread the machine and set it for a straight stitch
Insert a size 16/100 needle into your machine — check your machine's manual for the exact steps, as the process varies by brand. Thread the machine with thread that matches your jeans or is close enough that it will not stand out. Navy, black, or medium blue thread works for most jeans. Wind a bobbin with the same thread and insert it into the bobbin case.
Set the machine to a straight stitch (usually the default setting) and adjust the stitch length to 2.5 to 3 millimeters — this is a medium length that holds well on denim without creating a weak seam. Test the tension on a scrap of denim folded the same way as your hem. Sew a short line and check that the stitches look even on both sides. If the top thread is loose or bunched, adjust the tension dial slightly and test again.
Sew the hem with a slow, steady pace
Lay the first leg flat with the pinned hem facing up. Position the fabric so the needle will sew about a quarter inch from the fold — this keeps the hem from rolling and makes it less visible from the outside. Lower the presser foot and backstitch a few stitches to lock the thread, then sew forward slowly around the leg.
When you reach the inseam or outseam, the fabric will be very thick. Slow down even more, let the machine do the work, and do not force the fabric through. If the needle struggles or skips, stop with the needle down, lift the presser foot, and adjust the fabric slightly. Lower the foot and continue. Once you have gone all the way around and returned to where you started, backstitch a few stitches and cut the thread. Repeat for the second leg.
Trim excess fabric and finish the inside edge
Turn the jeans inside out and look at the hem from the inside. If there is more than half an inch of fabric above your stitch line, trim it down to about half an inch with scissors. This reduces bulk and makes the hem less likely to fray.
You can finish the raw edge by sewing a zigzag stitch along it, or you can leave it as is — most people do not bother with a zigzag on jeans because denim does not fray much. If you do want to zigzag, set your machine to a zigzag stitch and sew slowly along the cut edge, staying just inside the fabric so you do not sew off the edge.
Press the hem and wash the jeans to set the stitches
Lay the jeans flat and press the hem with an iron set to medium heat. Press from the inside first, then flip and press from the outside. This flattens the fold and makes the hem look neater. Let the jeans cool before you wear them.
Wash the jeans in cold water and hang them to dry, or tumble dry on low heat. The first wash will set the stitches and show you whether the hem is find. If you notice any loose threads or gaps, you can sew over that section again or hand-stitch it closed.
Frequently Asked Questions
What if my sewing machine skips stitches when I hit the seams?
Skipped stitches usually mean the needle is too small or the tension is wrong. Switch to a size 16/100 or 18/110 needle, which is heavier and handles thick fabric better. Slow down when you cross the seam and let the machine work without pushing the fabric. If it still skips, check that the needle is inserted correctly and that your thread is not tangled in the bobbin case.
Can I hem jeans without a sewing machine?
Yes, you can hand-stitch a hem using a needle and thread, but it takes longer and the stitches are more likely to come loose with wear. A sewing machine creates a stronger, more durable hem that holds up through many washes. If you do not have a machine, a tailor can hem jeans for a small fee.
Should I use a different thread color or type?
Match the thread to your jeans as closely as you can — navy, black, or medium blue for most jeans. Regular all-purpose polyester or cotton thread works fine. Avoid very light colors like white or cream, which will show on dark denim. Specialty threads like topstitching thread are thicker and more visible, so use them only if you want the stitches to stand out.
How much should I fold up for the hem?
Fold up about one to one and a half inches. This gives you enough fabric to sew through without the hem being too bulky. If you fold up less than an inch, the raw edge may show or fray. If you fold up more than two inches, the hem becomes stiff and uncomfortable.
What if one leg is longer than the other after I sew?
Unpin that leg, adjust the fold to the correct length, and sew it again. You can sew over the old stitches — just backstitch over them and sew a new line a quarter inch above or below the first one. Trim the old thread and the excess fabric, and press the new hem flat.