The Basic Process for Machine Hemming Pants
To hem pants on a sewing machine, you measure how much fabric to remove, fold and pin the new hem, and then sew a straight line around the pant leg using a straight stitch. The whole process takes 20 to 40 minutes per pair once you have the right measurements. You do not need special skills — a basic straight stitch and steady hand are enough.
The key is getting the length right before you cut. Pants should break slightly on top of your shoe when you stand, or sit just above the ankle if you prefer a cropped look. Have someone help you pin the hem while you wear the pants and shoes you will actually wear with them, or use a mirror and mark the length yourself with a fabric pen.
Key Takeaways
- Measure and mark the desired hem length while wearing the pants and the shoes you will pair them with, then fold the fabric up to that mark and pin it in place.
- Press the fold with an iron before sewing to create a sharp crease and make the fabric easier to guide under the presser foot.
- Use a straight stitch with thread that matches your fabric, sew slowly and keep the needle line about one-quarter inch from the fold, and backstitch at the start and end to lock the seam.
- Try on the pants after hemming to check the length and make sure the stitching is even; if the hem is uneven, you can remove the stitches and re-sew.
Measuring and Marking Your Hem Length
Put on the pants with the shoes you plan to wear them with, and stand in front of a mirror or have someone help you. Decide where you want the hem to fall — most people aim for the pants to break slightly on the shoe, meaning a small fold of fabric sits on top. Mark this line with a fabric pen or tailor's chalk, going all the way around the pant leg. If you are hemming both legs, mark both.
Measure from the floor up to your mark on both legs and write down the measurements. Pant legs are often uneven, so if one leg measures 28 inches and the other is 28.5 inches, you will need to hem them to different lengths. This is normal and necessary for the pants to hang evenly.
Once you have your measurements, take off the pants. Lay one pant leg flat on your work surface and measure from the bottom edge up to where you marked. This tells you how much fabric you will fold up. Add one-half inch to that number — this extra half inch is the turn-under, the part that folds back on itself inside the hem. For example, if you need to remove 2 inches of fabric, you will fold up 2.5 inches total.
Folding, Pinning, and Pressing the Hem
Lay the pant leg flat with the inside facing up. Fold the bottom edge up by the amount you calculated, so the raw edge of the fabric is now hidden inside the fold. The fold should be crisp and even all the way around. Pin the fold in place every 2 to 3 inches, pushing the pins through both layers of fabric so the hem stays put while you sew.
Before you sew, press the fold with an iron on a medium setting. This flattens the crease and makes the fabric much easier to feed under the presser foot. Let the fabric cool for a few seconds after pressing — warm fabric can stretch and shift. Press both pant legs this way before you move to the sewing machine.
Setting Up Your Sewing Machine and Thread
Thread your machine with thread that matches your pants as closely as you can. If you cannot find an exact match, choose a shade slightly darker than the fabric — darker thread is less visible than lighter thread. Use the same thread in both the top and bobbin.
Set your machine to a straight stitch with a stitch length of 2.0 to 2.5 millimeters. This is a standard length for hemming — long enough to hold the fabric securely but short enough that the stitches look neat. If your machine has a needle position dial, keep the needle centered. Test your settings on a scrap of fabric first if this is your first time hemming, so you know what the stitches will look like.
Sewing the Hem Stitch
Slide the pant leg under the presser foot so the needle will sew about one-quarter inch from the fold. This distance is called the seam allowance, and keeping it consistent all the way around makes the hem look professional. Lower the presser foot to hold the fabric in place.
Backstitch three or four stitches to lock the thread, then sew forward slowly and steadily around the entire pant leg. Keep your hands relaxed and let the feed dogs (the metal teeth under the presser foot) move the fabric — you are guiding, not pulling. Sew all the way around until you reach where you started, then backstitch again to lock the end. Cut the thread, leaving a 4-inch tail.
Repeat this process for the second pant leg. If the legs are different lengths, adjust your starting point so the seam allowance stays one-quarter inch from the fold on both legs.
Checking Your Work and Fixing Mistakes
Try on the pants right-side out and check the hem length in a mirror. The hem should be even all the way around, and the stitching should not be visible from the outside. If the length is off by a small amount — less than one-quarter inch — it is usually not worth re-doing. If it is noticeably uneven or too long, you can remove the stitches and re-sew.
To remove stitches, use a seam ripper or small scissors to cut every third or fourth stitch, then pull the thread out. Fold and press the hem again, and sew a new line one-quarter inch from the fold. The old stitch holes will be hidden under the new stitches.
Once you are happy with the length, trim any loose threads and press the hem one more time with an iron. This sets the stitches and gives the hem a finished look.
Common Mistakes and How to Avoid Them
The most common mistake is sewing too close to the fold — if your seam is right at the edge, the fold can roll and the hem will look wavy. Stay one-quarter inch away from the fold. Another mistake is sewing too fast, which causes uneven stitches and can pull the fabric. Slow down and let the machine do the work.
Skipping the iron press is also a frequent error. Pressing the fold before you sew makes the fabric stable and much easier to sew in a straight line. If you skip this step, the fabric will shift under the presser foot and your hem will be crooked.
Finally, do not sew over pins. Remove each pin just before the needle reaches it, or sew with pins running parallel to the needle rather than across it. Hitting a pin can break your needle or damage the machine.
Frequently Asked Questions
Can I use a serger instead of a regular sewing machine to hem pants?
Yes, a serger creates a more finished edge and is faster, but it is not necessary for a basic hem. A regular sewing machine with a straight stitch works just as well and is what most people have. If you own a serger, use a 3-thread or 4-thread stitch and follow the same measuring and pinning steps.
What if my pant legs are very different lengths?
Measure each leg separately and hem them to their own correct length. This is common and normal — most people's legs are slightly different. Sew each leg as a separate project, adjusting your starting point so the seam allowance stays consistent on both.
Do I need to fold the hem twice, or just once?
Folding once is fine for most fabrics. You fold the raw edge up, and the fold itself becomes the bottom edge of the hem. If your fabric frays easily (like linen or loosely woven cotton), you can fold twice — fold up once, press, then fold up again — so the raw edge is completely enclosed. This takes longer but prevents fraying over time.
How do I hem stretchy fabrics like knit pants?
Use a ballpoint needle instead of a regular needle, and set your machine to a narrow zigzag stitch instead of a straight stitch. The zigzag allows the fabric to stretch without breaking the thread. Follow the same measuring and pressing steps, but sew more slowly since knit fabric can shift.
What thread weight should I use for hemming?
Use all-purpose polyester or cotton thread in a weight that matches your fabric. For lightweight fabrics like cotton or linen, use regular all-purpose thread. For heavier fabrics like denim or canvas, you can use the same all-purpose thread — your machine will handle it fine. Do not use heavy-duty thread unless your fabric is very thick, as it can create visible stitches.