A basic machine hem takes five steps and holds through dozens of washes
A machine hem is stronger than a hand-sewn one and takes about 15 minutes once you measure. You fold the fabric edge up twice to hide the raw edge, pin it in place, and sew a straight line near the fold. The two layers of fabric you've created trap the thread and keep the hem from unraveling. A standard hem works on pants, skirts, dresses, and most woven fabrics—anything from cotton to linen to lightweight wool.
The basic process is the same whether you're hemming new fabric or shortening something you already own. The main difference is that with an existing garment, you'll measure from the original hem line rather than from scratch. Most people can learn this in one try and produce a hem that looks intentional and lasts years.
Key Takeaways
- Measure twice from the floor or a flat surface, mark with chalk or a fabric pen, and cut only after confirming the length is even on all sides.
- Fold the raw edge up a quarter inch, then fold it up again by the full hem width you want (usually half an inch to an inch), and press with an iron to crease the fold.
- Pin the fold every two to three inches, keeping pins perpendicular to the fold so the presser foot can move over them without stopping.
- Sew a straight line close to the inner fold using a thread color that matches your fabric, and backstitch at the start and end to lock the stitches.
- Press the finished hem flat with an iron to set the crease and make the stitches less visible.
Measure the length before you cut anything
Put on the garment or lay the fabric flat on a table and measure from the floor or a straight edge to where you want the hem to end. Use a ruler, measuring tape, or a hem gauge—a small metal ruler with a sliding marker that costs a few dollars and makes this step faster. Mark the line with tailor's chalk or a fabric pen that washes out. Go all the way around the garment or fabric, checking that the line is level and even.
If you're hemming pants, have someone help you stand still while they mark, or use a full-length mirror and mark as you stand. Uneven hems are the most common mistake, and they're visible from across a room. Take the extra minute to double-check that your marks are at the same height all the way around.
Once you're certain the line is right, cut the fabric straight across about half an inch below your marked line. This extra half inch becomes part of the hem and gets folded up. If you cut too close to the line, you won't have enough fabric to fold and the hem will be weak.
Fold and press the hem twice
Fold the raw edge of the fabric up a quarter inch and press it flat with an iron on medium heat. This first fold hides the raw edge so it doesn't fray and look unfinished inside the garment. Use a pressing cloth (a thin cotton cloth or even a clean kitchen towel) between the iron and the fabric if you're working with delicate material or synthetic fibers that can melt.
Now fold the fabric up again by the width you want your finished hem to be. Most hems are half an inch to one inch wide—half an inch is standard for pants and skirts, one inch for dresses and heavier fabrics. Press this second fold flat as well. The crease you create with the iron makes the fabric stay in place while you sew and produces a neater finished line.
If the fabric is slippery or stretchy, let it cool for a minute after pressing before you move it. Warm fabric can shift out of place easily. You can also use a spray starch or fabric stiffener before pressing if the material keeps sliding—these products are sold in the laundry aisle and wash out later.
Pin the fold every two to three inches
Place pins perpendicular to the fold—that is, the pin goes straight through the fold from front to back, not along the length of the hem. Space them two to three inches apart all the way around. Pins placed this way won't catch the presser foot of your sewing machine as it moves, and they're straightforward to remove as you sew.
If a pin is in the way of the presser foot, straightforward pull it out as you approach it. You don't need to stop the machine. Pins placed along the length of the hem (parallel to the fold) will catch the foot and can break the needle or damage the machine, so avoid that placement.
Check that the fold is still crisp and even after pinning. If the fabric has shifted, re-press the section that moved before you start sewing.
Sew a straight line close to the inner fold
Thread your machine with thread that matches your fabric color. If you can't find an exact match, choose a shade slightly darker rather than lighter—darker thread is less visible on seams. Use the same thread weight and fiber as the rest of the garment if possible (polyester thread for polyester fabric, cotton for cotton).
Set the machine to a straight stitch with a stitch length of 2.0 to 2.5 millimeters. This length is standard for most sewing and produces a line of stitches that's tight enough to hold but not so tight that it puckers the fabric. Consult your machine's manual if you're unsure how to adjust stitch length—the dial or button is usually on the front or side of the machine.
Position the fabric under the presser foot so the needle will sew close to the inner fold—about an eighth of an inch from the fold. This placement hides the stitches inside the hem and produces a professional look. Backstitch at the start (sew backward a few stitches, then forward) and at the end to lock the thread so it doesn't unravel. Sew slowly and steadily, removing pins as you approach them.
Press the finished hem to set the crease
Once you've sewn all the way around, press the entire hem flat with an iron on medium heat. This step sets the crease, flattens the stitches so they're less visible, and gives the hem a finished appearance. Press from the inside of the garment if possible—this protects the outside from shine marks that an iron can leave on some fabrics.
Let the garment cool completely before wearing or washing it. The heat from the iron helps the fabric hold its shape, and moving it while it's still warm can undo that work. If the hem looks wavy or puckered after pressing, the fabric may have shifted while you were sewing. This is fixable: straightforward re-press the section that's uneven, and if it doesn't improve, you can carefully cut the stitches with a seam ripper and re-sew that section.
Common mistakes and how to fix them
Uneven hem line. This is the most visible mistake and the hardest to fix. If one side is noticeably shorter than the other, you'll need to remove the stitches with a seam ripper, re-measure, and sew again. A seam ripper is a small tool with a curved blade that cuts thread without damaging fabric—they cost a few dollars and are worth having. To avoid this, measure multiple times before cutting and use a level or a hem gauge to keep your line straight.
Puckered or wavy stitches. This usually means the fabric shifted while you were sewing or the thread tension was too tight. Check your machine's manual for how to adjust tension (it's usually a dial on the front). If the puckering is minor, pressing the hem flat often makes it disappear. If it's severe, remove the stitches and sew again with looser tension.
Stitches that show on the outside. You sewed too close to the outer edge of the fold, or the fold wasn't pressed firmly enough. This won't affect how the hem holds, but it looks unfinished. On future hems, sew closer to the inner fold and press harder before sewing.
Hem that comes loose after washing. You didn't backstitch at the start and end, or the thread tension was too loose. Always backstitch, and check that your tension is set correctly by sewing a test line on scrap fabric first. If a hem has already come loose, you can re-sew just the loose section rather than the whole hem.
Frequently Asked Questions
What kind of thread should I use?
Use all-purpose polyester or cotton thread in a color that matches your fabric. Polyester is stronger and works on most materials. If your garment is made of natural fiber like cotton or linen, cotton thread blends in better, but polyester works fine too. Avoid heavy-duty thread unless you're hemming very thick fabric like denim or canvas.
Can I hem stretchy fabric like knit or jersey?
Yes, but use a ballpoint needle (designed for knits) and a stretch stitch if your machine has one, or a narrow zigzag stitch instead of a straight stitch. Stretch stitches move with the fabric and won't break when you wear the garment. Straight stitches on knits can snap because the fabric moves more than the thread. Test on a scrap first.
How do I fix a hem that's puckered after I've already sewn it?
Press it flat with an iron on medium heat and let it cool completely. Most minor puckering disappears with pressing. If it's still visible, you can carefully remove the stitches with a seam ripper and re-sew that section with slightly looser thread tension. Puckering usually means the fabric shifted or the tension was too tight.
Do I have to press the hem before sewing, or can I just pin it?
Pressing makes the hem much easier to sew neatly because the crease holds the fold in place. If you skip pressing, the fabric can shift as you sew and the hem line won't be straight. Pressing takes two minutes and is worth the time. Use medium heat and let the fabric cool before sewing.
What if my hem is too short after I've sewn it?
You can't make it longer without removing the old stitches and starting over. This is why measuring twice before cutting is important. If the hem is only slightly too short, you might be able to let out the fold a little and re-sew, but you'll lose some of the original hem width. For future projects, cut conservatively and measure from the floor while wearing the garment.