Hemming jeans on a sewing machine takes about 20 minutes once you measure and pin
To hem jeans on a sewing machine, you measure how much fabric to remove, fold and pin the new hem, then sew a straight stitch along the fold. The whole process—measuring, pinning, and sewing—takes roughly 20 to 30 minutes for a beginner. You do not need special skills; a basic straight stitch is all you need, and most mistakes are fixable by picking out stitches and trying again.
The hardest part is usually getting the hem length right before you sew, because jeans are thick and the fold can shift as you work. The second-hardest part is sewing through the thick seams at the inseam and outseam without breaking a needle. Both are manageable if you go slowly and use the right needle size.
Key Takeaways
- Measure the hem length while wearing the jeans with the shoes you will wear them with, because heel height changes the length you need.
- Use a size 16 or 18 needle in your machine when sewing through the thick seams of jeans, because a smaller needle can break.
- Fold the hem twice—once to hide the raw edge, then again to create the fold you will sew—so the inside looks finished.
- Sew slowly when you reach the inseam and outseam, and stop with the needle down if the presser foot lifts, so you do not shift the fabric.
- If your stitches look uneven or you hit a seam wrong, pick out the thread with a seam ripper and sew that section again.
Measure the hem length while wearing the jeans
Put on the jeans with the shoes you plan to wear them with most often. Stand in front of a mirror or have someone help you. The hem should break slightly on the top of your shoe—meaning a small fold of fabric sits on the shoe, not a gap between the pant leg and the shoe. If you like a shorter or longer look, adjust, but the break point is the standard starting place.
Measure from the floor to where you want the hem to end. Write this number down. Then measure the current length of one pant leg from the waistband to the hem. Subtract the new length from the old length. That number is how much fabric you will remove. For example, if the pant leg is currently 32 inches and you want it to be 30 inches, you will remove 2 inches total.
Take off the jeans and lay one leg flat on a table. Measure down from the current hem by half the amount you are removing. If you are removing 2 inches total, measure down 1 inch. Mark this spot with a fabric pen or chalk. Repeat on the other leg so both are even.
Fold and pin the new hem
Fold the pant leg up along the line you marked, with the wrong side of the fabric facing out (the inside of the pant leg facing you). Press the fold flat with your hand or an iron on low heat. This is your first fold.
Now fold the raw edge up again, tucking it inside the first fold so no raw edge shows. This second fold should be about half an inch wide. Pin this fold every 2 to 3 inches all the way around the pant leg. Use straight pins, not safety pins. The pins should go through all layers and sit perpendicular to the fold, so the presser foot can push them out as you sew.
Repeat on the other pant leg. Try the jeans on to check the length before you sew. If the length is wrong, unpin, unfold, and remeasure. It is much faster to fix now than to pick out stitches later.
Set up your machine and thread it
Insert a size 16 or 18 needle into your machine. Jeans fabric is thick, and a smaller needle (like a size 11) can break when it hits the seams. Check your machine manual for how to insert the needle correctly—the flat side usually faces a certain direction.
Thread your machine with thread that matches the jeans or is a neutral color like navy or black. Use the same thread in the bobbin. Wind the bobbin by hand if you are new to this, because it is easier to control the tension. Set your machine to a straight stitch with a stitch length of 2.5 to 3 millimeters—this is a standard length for hemming and will hold the fabric securely without puckering.
Test your tension on a scrap of folded denim before you start on the actual jeans. Sew a few inches and check that the stitches look even on both sides. If the top thread is loose and loopy on the back, tighten the top tension slightly. If the bobbin thread is loose on the front, tighten the bobbin tension.
Sew the hem with a straight stitch
Place the first pant leg under the presser foot with the fold facing you. Position the needle so it will sew about a quarter inch from the fold—close enough to hold the hem but not so close that it catches the fold itself. Lower the presser foot and sew forward slowly, removing pins as you approach them.
When you reach the inseam (the seam that runs up the inside of the leg), slow down even more. The fabric is three or four layers thick here. If the presser foot starts to lift, stop with the needle down in the fabric, raise the presser foot, and adjust the fabric so it sits flat again. Lower the presser foot and continue. Do the same at the outseam on the outside of the leg.
Sew all the way around until you reach where you started. Overlap your stitches by about half an inch, then backstitch three or four times to lock the thread. Trim the thread ends with scissors. Repeat on the other pant leg.
Press the hem and try on the jeans
Turn the pant leg right-side out and lay it flat. Press the hem with an iron on medium heat, pressing from the inside first, then the outside. This sets the stitches and makes the hem look crisp. Let the jeans cool for a minute before you try them on.
Put on the jeans and check the length and how the hem sits. The stitches should be straight and even, and the hem should not pucker or pull. If one leg is slightly longer than the other, you can adjust it by picking out the stitches on the longer leg and resewing it higher. If the stitches are very uneven or the hem is puckered, pick out the entire hem with a seam ripper and try again—it is not a failure, it is practice.
Common mistakes and how to fix them
The most common mistake is sewing too close to the fold, which catches the fold itself and creates a visible line on the outside of the jeans. If this happens, pick out the stitches and sew again a quarter inch farther from the fold. Another common mistake is not removing pins before the presser foot reaches them, which can bend the needle or break it. Always remove pins by hand as you sew, never sew over them.
Uneven stitches usually mean you were going too fast or the fabric shifted. Pick out that section and sew it again slowly, keeping your hands still and letting the machine do the work. If you broke a needle, replace it with a fresh size 16 or 18 and check that it is inserted correctly before you start again. A bent needle will make worse stitches and can damage your machine.
If the hem puckers after you press it, the tension was too tight. Loosen the top tension by one number and sew a test seam on scrap fabric before you try the jeans again. If the hem is wavy instead of straight, the presser foot pressure may be too high, or you may have stretched the fabric as you sewed. Adjust the pressure if your machine has that option, and sew the next leg more slowly.
Frequently Asked Questions
Can I hem jeans if they have a thick original hem?
Yes, but you will need to remove the original hem first. Use a seam ripper to cut and pull out the old stitches, then trim away the old hem fabric. Wash and dry the jeans to remove any loose threads, then measure and pin the new hem as usual. This adds 10 to 15 minutes to the job but is the only way to get a clean result.
What if my needle keeps breaking when I hit the seams?
You are likely using a needle that is too small for the thickness of denim. Switch to a size 18 needle, which is thicker and stronger. If you still break needles, stop with the needle down when you reach a seam, raise the presser foot, and manually turn the wheel to move the needle down one stitch at a time through the thick part. This gives you more control and prevents the needle from bending.
Do I have to fold the hem twice, or can I just fold it once?
Folding twice hides the raw edge and makes the inside of the jeans look finished, which is why it is standard. If you fold only once, the raw edge will show on the inside and may fray over time. Folding twice takes only a few extra minutes and is worth doing.
How do I know if my thread tension is right?
Sew a test seam on folded scrap denim and look at both sides. The stitches should look the same on the front and back—small, even, and tight. If the top thread is loopy on the back, the top tension is too loose. If the bobbin thread is loopy on the front, the bobbin tension is too loose. Adjust one at a time and test again.
Can I hem jeans by hand instead of using a machine?
Yes, but it takes much longer—usually 45 minutes to an hour—and the stitches are more visible. A machine hem is faster, stronger, and looks more professional. If you do not have access to a machine, a hand-sewn hem using a ladder stitch (also called an invisible stitch) will work, but you will need a needle, thread, and patience.