The basic steps to hem pants on a machine

Hemming pants on a sewing machine takes about 20 to 30 minutes once you have the right measurements. You will need the pants, a measuring tape, pins, thread that matches the fabric, scissors, and an iron. The process is: measure and mark the new hem length, fold the fabric up to that mark, pin it in place, sew along the fold with a straight stitch, and trim the excess fabric inside the hem.

The most common mistake is not pressing the fold flat before sewing. A crease that is not ironed down will shift as you sew, and your hem line will be uneven. Spend 30 seconds with an iron on the fold before you sit down at the machine.

If you are hemming for the first time, start with a straightforward straight hem on a pair of cotton pants or jeans. Knit fabrics and stretchy materials are harder to keep flat while sewing and are better left for later.

Key Takeaways

  • Measure the desired hem length while wearing the shoes you will wear with the pants, and mark it with pins or tailor's chalk on both legs.
  • Press the fold flat with an iron before sewing, or the hem will pucker and shift as the needle moves.
  • Use a straight stitch on a medium stitch length (2.0 to 2.5 mm), and sew parallel to the fold about one-quarter inch up from the edge.
  • Trim the raw fabric edge inside the hem to one-quarter inch, then fold it under and sew again for a finished hem that will not fray.

Measuring and marking the hem length

Put on the pants with the shoes you plan to wear them with. Stand in front of a mirror and have someone else measure from the floor to where you want the hem to end. Mark that point on both pant legs with pins placed horizontally across the inside of the leg, or use tailor's chalk to draw a line. The hem should be the same length on both legs, so measure both sides even if they feel the same.

If you are hemming alone, stand on a flat surface and use a measuring tape to check the distance from the floor to your mark on each leg. Take the measurement at least three points on each leg — the inside seam, the center front, and the outside seam — to catch any unevenness in how the pants hang.

Once you have marked both legs, take the pants off and lay them flat on your work surface. Fold the fabric up along your marked line and pin the fold in place every two inches or so. The pins should go through both layers and hold the fold steady.

Preparing the fabric for sewing

Set your iron to the heat level for the fabric type — cotton and linen can take high heat, while synthetics need medium heat. Press the folded hem firmly for 10 to 15 seconds, then let it cool before you move the pants. A warm crease will relax and shift if you pick up the pants right away.

Check that the fold is even along the entire hem. If one section is higher or lower than the rest, unfold that part, re-pin it, and press again. Uneven pressure or a fold that was not quite straight will show as a wavy line when you sew.

Once the crease is set, you can remove the pins if they are in the way of your sewing machine foot, but keep the fold in place. Some people prefer to leave the pins in and sew around them — this works if your machine has enough clearance, but it is safer to remove them and rely on the pressed crease to hold the fold.

Setting up the sewing machine

Thread the machine with thread that matches the color of the pants as closely as you can. If the fabric is a color you cannot match exactly, choose a shade slightly darker rather than lighter — a darker thread is less visible on fabric than a lighter one. Wind a bobbin with the same thread and insert it into the bobbin case.

Set the stitch to a straight stitch and the stitch length to 2.0 to 2.5 millimeters. This length is small enough to hold the hem securely but large enough that you can remove stitches later if you need to adjust the hem. A stitch length shorter than 2.0 mm can pucker the fabric, especially on lighter materials.

Lower the presser foot and position the pants under the needle so that the needle will sew about one-quarter inch up from the fold. This distance keeps the stitch line close enough to the fold to hold it flat but far enough away that the stitches will not show on the outside of the pant leg when you wear them.

Sewing the hem

Start sewing at a side seam if possible — this gives you a natural anchor point and makes it easier to keep the line straight. Sew slowly and keep the fold aligned with the edge of the presser foot or a marked line on the needle plate. Most machines have a line marked one-quarter inch from the needle; use it as a guide.

Sew all the way around the pant leg, keeping the same distance from the fold. When you reach the point where you started, overlap the stitches by about one-half inch and then backstitch to lock the thread. Cut the thread and remove the pants from the machine.

If you are sewing a double hem — which is more durable and looks more finished — fold the raw edge of the fabric up another one-quarter inch, press it, and sew along that fold as well. This second line of stitching encloses the raw edge and prevents fraying.

Finishing and trimming

Turn the pants inside out and look at the hem. If the stitching is straight and even, trim the raw fabric edge to one-quarter inch above the stitch line using sharp scissors or a rotary cutter. Be careful not to cut through the stitches themselves.

If you want a finished hem that will not fray, fold that trimmed edge under by one-quarter inch and sew it down with another line of stitching. This creates a clean, enclosed hem that looks professional and lasts longer. If the fabric does not fray easily — like denim or heavy cotton — you can skip this step.

Press the finished hem from the inside with an iron to set the stitches and remove any wrinkles. Try on the pants to make sure the length is correct and the hem hangs evenly. If the length is off by a small amount, you can adjust it by removing the stitches with a seam ripper and re-sewing at a different distance from the fold.

Common problems and how to fix them

If the hem is wavy or puckered, the fold was probably not pressed flat before sewing, or the fabric shifted while you were sewing. Remove the stitches with a seam ripper, press the fold again, and sew a new line of stitches. Sew more slowly the second time and keep steady pressure on the fabric to prevent shifting.

If the hem is uneven — higher on one side than the other — you did not measure both legs carefully enough. Remove the stitches, re-measure with the pants on, and sew again. This is a common issue with pants that have one leg longer than the other due to how they were cut or how you wear them.

If the thread is visible on the outside of the pant leg, you sewed too close to the fold. This is usually not a problem if the thread matches the fabric color, but if it bothers you, you can remove the stitches and sew again one-quarter inch farther from the fold. You will need to trim the excess fabric inside the hem to make room for the new stitch line.

Frequently Asked Questions

Can I hem stretchy pants or knit fabrics on a regular sewing machine?

Yes, but you need to use a ballpoint needle instead of a regular needle, and a stitch that has some give to it — like a narrow zigzag or a stretch stitch — instead of a straight stitch. Knit fabrics curl and shift more than woven fabrics, so press the fold very firmly and sew slowly. If the hem still puckers, try a slightly longer stitch length.

What if my sewing machine does not have a straight stitch?

Most machines have a straight stitch as the default, but if yours does not, look for a stitch that looks like a straightforward line of dashes. Check your machine's manual to find the stitch number or symbol. If you cannot find a straight stitch, a narrow zigzag will work, though it will be slightly less neat.

How do I know if my thread color matches well enough?

Hold the thread next to the fabric in natural light, not under a lamp. If the thread looks the same color or slightly darker, it will be fine. Sew a test line on a scrap of the same fabric and look at it in daylight. If you cannot see the stitches from a few inches away, the match is good enough.

Can I hem pants without an iron?

You can, but the hem will be harder to keep straight and may come out wavy. If you do not have an iron, fold the hem carefully and pin it very securely every inch or so, then sew slowly and keep steady tension on the fabric. The result will not be as neat as a pressed hem, but it will hold.

How long does a sewn hem last?

A hem sewn with a straight stitch on a sewing machine will last through many washings and wearings if the thread is strong and the stitches are find. If you sew a double hem or finish the raw edge, it will last even longer. Hems on jeans and heavy fabrics typically outlast hems on lighter materials.