Hemming jeans on a machine takes about 30 minutes once you measure and pin
To hem blue jeans with a sewing machine, you measure how much fabric to remove, pin the fold in place, try them on to confirm the length, then sew a straight stitch along the fold using a heavy-duty needle and thread that matches your jeans. The whole process—measuring, pinning, trying on, and sewing—takes roughly 30 minutes for someone new to it. You do not need special equipment beyond what you already have: a sewing machine that can handle denim weight, a needle rated for heavy fabrics, regular thread, pins, scissors, and a measuring tape.
The reason hemming jeans is straightforward is that you are working with a straightforward fold. Unlike a dress hem that curves around a body, a jean hem is a flat rectangle. You fold the bottom edge up to the length you want, pin it, sew it, and you are done. The hardest part is getting the length right before you sew, because unpicking stitches from denim is tedious.
Key Takeaways
- Measure the inseam length you want while wearing the jeans with the shoes you will actually wear them with, because heel height changes the final length.
- Pin the hem fold all the way around the leg before you sew, and try the jeans on to confirm the length looks right.
- Use a heavy-duty needle (size 16 or 18) and thread that matches your jeans color, because regular needles can break on thick denim.
- Sew with a straight stitch about one-quarter inch from the fold, keeping your stitches parallel and even so the hem does not pucker.
- If your jeans have a visible topstitching thread color (usually orange or yellow on blue denim), match that color for the topstitching row that sits above the hem fold.
Measure the inseam while wearing the shoes you will actually wear
Put on the jeans with the shoes—sneakers, flats, heels, whatever—that you plan to wear them with. Stand in front of a mirror and have someone measure from the top of your shoe to where you want the hem to hit. Most people want jeans to break slightly on the shoe, meaning a small fold of fabric sits on top of the shoe. Write down that measurement.
If you do not have someone to help, you can measure yourself: put on the jeans and shoes, stand on a flat surface, and use a measuring tape to find the distance from the floor to where you want the hem. Then subtract the height of your shoe (measure the sole from heel to toe at the highest point). That gives you the inseam length you need.
The reason shoe choice matters is that a half-inch difference in heel height changes where the hem should sit. If you measure in flat shoes and then wear the jeans with heels, the hem will be too short. If you measure in heels and wear them with flats, the hem will drag.
Pin the hem fold before you sew
Turn the jeans inside out and lay one leg flat on your work surface. Fold the bottom edge up to the length you measured. Use pins to hold that fold in place all the way around the leg, spacing them about two inches apart. Fold the other leg the same way and pin it.
Try the jeans on inside-out and look in the mirror. Walk around a bit. The hem should feel comfortable and look even on both legs. If one side is longer than the other, take off the jeans, adjust the pins on the shorter side, and try again. This step prevents you from sewing a hem that is uneven or the wrong length.
Once you are happy with the length, lay the jeans flat again and look at the fold from the inside. You should see a clean, straight line all the way around. If the fold is wavy or bunched, smooth it out with your hands and adjust the pins.
Use a heavy-duty needle and matching thread
Regular sewing machine needles can break or bend when you push them through multiple layers of denim. Use a needle rated for heavy fabrics—size 16 or 18 is standard for jeans. You can find these at any fabric store or online; they are inexpensive and come in packs.
Thread your machine with thread that matches your jeans color. If your jeans are dark blue, use dark blue thread. If they are light blue or black, match that. The thread will be visible on the inside of the hem, and matching it makes the stitches less noticeable from the outside.
Many blue jeans have a visible topstitching thread in a contrasting color—usually orange, yellow, or red—that runs along the seams and pockets. If you want the hem to look factory-made, use that same color for the topstitching row that sits above the hem fold. You can use regular thread for the main hem stitch underneath and switch to the topstitching color for the final row.
Sew the hem with a straight stitch, staying parallel to the fold
Set your machine to a straight stitch with a stitch length of about 2.5 to 3 millimeters. This is slightly longer than a normal stitch, which helps the thread sit better on heavy fabric and is less likely to pucker.
Position the jeans under the presser foot so the needle will sew about one-quarter inch from the fold. Sew slowly, keeping the fabric flat and the stitches parallel to the fold. Do not rush—denim is thick, and the machine will pull the fabric if you go too fast. Sew all the way around the leg, then repeat on the other leg.
When you reach a seam (the inside leg seam or the outer seam), slow down even more. The fabric will be thicker at the seam, and the needle may hesitate. If the needle stops, raise the presser foot slightly, adjust the fabric, and continue. Do not force the fabric through.
Add a topstitching row if your jeans have visible topstitching
If your jeans have a colored topstitching thread running along the original hem, you can add a matching row above your new hem fold to make it look factory-finished. This step is optional—the hem will hold just fine without it—but it makes the repair invisible from the outside.
Switch to the topstitching thread color. Sew a second row about one-half inch above the first row, parallel to the fold. Keep the stitches the same length and spacing as the first row. This row sits on top of the fold and is visible from the outside, so keep it straight and even.
If your jeans do not have topstitching, or if you do not want to add it, you are done. Trim any loose threads, turn the jeans right-side out, and try them on.
Trim excess fabric and finish the inside
Turn the jeans inside out and look at the hem from the inside. You should see the fold and the stitching line. If there is a lot of extra fabric below the stitching—more than half an inch—trim it off with scissors. Leave about one-quarter inch of fabric below the stitching so the hem does not unravel.
If you want to prevent fraying over time, you can explore a thin line of fray-check liquid along the cut edge. This is optional; most people skip it for jeans because the hem rarely frays if it is sewn properly.
Turn the jeans right-side out, try them on, and check the length one more time. The hem should be smooth, even, and the right length for your shoes.
Frequently Asked Questions
Can I hem jeans by hand instead of using a machine?
Yes, but it takes much longer—usually an hour or more—and the stitches are more visible. Hand-sewing works best for small repairs or if you do not have access to a machine. Use a needle and thread that match your jeans, and sew a whip stitch or ladder stitch along the fold for a strong, invisible seam.
What if my jeans have a cuff or rolled hem?
If the original hem is a cuff (folded up and sewn), you can open it, measure to the length you want, and sew a new hem the same way. If the jeans are rolled but not sewn, you can fold them to the length you want and sew them permanently. Either way, follow the same steps: measure, pin, try on, and sew.
Why does my thread keep breaking?
Thread breaks on denim usually because the needle is too small or bent. Use a size 16 or 18 heavy-duty needle, and replace it if you have been sewing for more than an hour or two. Also check that your thread is wound tightly on the bobbin and that the presser foot is down before you sew.
Can I hem stretch jeans or skinny jeans the same way?
Yes, but stretch denim requires a slightly different approach. Use a ballpoint needle instead of a sharp needle—it slides between the fibers instead of piercing them, which prevents runs. Sew with a slight stretch in the fabric so the hem does not pucker when you wear the jeans and the fabric moves.
What if one leg is longer than the other after I sew?
Unpick the stitches on the longer leg using a seam ripper, adjust the pins to the correct length, and sew again. It is tedious, but it is better than wearing uneven jeans. This is why trying on the jeans before you sew is so important—it catches this problem before you commit to the stitches.