Measure and mark the correct hem length before you cut

Put on the pants with the shoes you plan to wear them with, and stand in front of a mirror. The hem should break slightly on the top of your shoe — that means the fabric just touches the shoe without bunching or riding up. Have someone measure from the floor to where you want the hem to end, or use a measuring tape yourself by standing on a small step stool. Write this measurement down.

Take off the pants and lay them flat on a table. Measure up from the bottom of each pant leg to your target length and mark it with tailor's chalk or a fabric pencil. Mark all the way around both legs. This is your cutting line — you will cut about half an inch below this line to leave room for the fold.

Try the pants on one more time to double-check the marks look even. Uneven hems are the most common mistake, and it is much easier to catch it now than after you have sewn.

Key Takeaways

  • Measure the hem length while wearing the shoes you will wear with the pants, and mark both legs at the same height from the floor.
  • Cut the fabric about half an inch below your marked line, then fold the raw edge up and press it with an iron before sewing.
  • Use a straight stitch on a medium stitch length (2.5 to 3.0 mm) and sew as close to the fold as possible without the needle hitting the fold itself.
  • Backstitch at the start and end of each seam to lock the thread, and press the finished hem with an iron to set the crease.

Cut the fabric and prepare the fold

Cut along the line about half an inch below your chalk mark. Use sharp fabric scissors or a rotary cutter — dull scissors will pull the fabric and create an uneven edge. Cut slowly and keep the scissors perpendicular to the fabric so the cut is clean.

Fold the raw edge up toward the inside of the pant leg by about a quarter inch. This fold hides the raw edge and makes the hem look finished. Press this fold flat with an iron set to the temperature recommended for your fabric (check the care tag on the pants). Let it cool for a few seconds before moving on.

Now fold the entire hem up to your marked line and press again. You should have a clean, sharp crease that runs all the way around the pant leg. This crease is your sewing guide — you will follow it with your needle.

Thread the machine and set the stitch

Wind a bobbin with thread that matches the color of your pants. Thread the needle with the same color. Use a straight stitch and set the stitch length to 2.5 to 3.0 mm — this is a standard length for hemming. Too short and the thread will bunch; too long and the stitches will be loose and visible.

Test the tension on a scrap of fabric folded the same way as your hem. Sew a few inches and look at both sides. The top thread and bobbin thread should lock in the middle of the fabric, not pull to one side. If the top thread is loose on the back, tighten the top tension slightly. If the bobbin thread is loose on top, loosen the top tension. Most machines have a tension dial numbered 0 to 9 — start at 5 and adjust from there.

Sew the hem with a straight stitch

Pin the hem in place every 3 to 4 inches around the pant leg, pinning perpendicular to the fold so the pins do not get in the way of the needle. Slide the pant leg under the presser foot so the needle is about an eighth of an inch away from the fold — close enough to catch the fold, but not so close that the needle hits it and breaks.

Lower the presser foot and backstitch three or four stitches to lock the thread. Then sew forward slowly, following the crease as your guide. Keep the fold just to the left of the needle so you can see it the whole time. Sew all the way around the pant leg until you reach where you started, then backstitch again to lock the thread at the end.

Remove the pins as you go — do not sew over them. Sewing over a pin can break the needle and damage the machine. If you reach a pin before you are ready to remove it, stop with the needle down, lift the presser foot, pull out the pin, lower the presser foot, and continue.

Trim loose threads and press the finished hem

Cut the thread tails at the start and end of the seam as close to the fabric as possible. Trim any loose threads hanging from the bobbin side as well. Turn the pant leg inside out and look at your stitching — it should be straight and even all the way around.

Lay the pant leg flat on an ironing board with the hem facing up. Press the entire hem with an iron set to the correct temperature for your fabric. This sets the crease and makes the hem look professional. Press from the inside first, then flip and press from the outside. Let the pants cool completely before trying them on.

Common mistakes and how to avoid them

The most common error is sewing too close to the fold or actually sewing through the fold itself. This creates a visible line of stitching on the outside of the pant leg. The needle should run just below the fold, catching the hem fabric but not the fold edge. If you make this mistake, you can carefully cut out the stitches with a seam ripper and try again.

Uneven hems happen when you do not measure carefully at the start. Take time to mark both legs at the exact same height, and try the pants on before cutting. If one leg ends up shorter than the other, you can open the seam on the longer leg and re-sew it higher up.

Puckering — small wrinkles in the fabric around the seam — usually means the tension is too tight. Loosen the top tension by one or two numbers and test on a scrap before hemming again. Skipped stitches (places where the needle did not catch the thread) often mean the needle is bent or dull. Replace the needle and try again.

Hemming different pant styles

Straight-leg and slim-fit pants are the easiest to hem because the leg does not taper. Measure and sew as described above. Tapered pants and skinny jeans are trickier because the leg gets narrower at the bottom. Measure the hem length at the widest part of the leg opening, not at the very edge, so the fabric does not pull when you wear the pants.

Pants with a cuff — a folded band at the bottom — should be hemmed above the cuff, not through it. Measure to the top of the cuff, mark, and sew. Do not cut into the cuff itself. If the cuff is sewn on, you may need to open it, hem the pant leg, and re-sew the cuff, or take the pants to a tailor.

Frequently Asked Questions

Can I hem pants by hand instead of with a machine?

Yes. A hand-sewn hem using a blind stitch or whip stitch is less visible than a machine stitch and works well for dress pants. It takes longer — usually 20 to 30 minutes per pant leg — but gives a more tailored look. Use a needle and thread that match the fabric color, and sew with small, tight stitches.

What if I sew the hem too short?

If you sewed it only slightly too short, you can open the seam with a seam ripper, unfold the hem, and re-sew it lower. If you cut the fabric too short to let out, the pants cannot be fixed at home — you would need to take them to a tailor who can add a new hem band or patch.

Do I need to use a special presser foot for hemming?

A standard presser foot works fine for hemming. Some machines have a blind hem foot that makes invisible hems easier, but it is not required. If your machine has one and you want to use it, follow your machine's manual for setup and stitch selection.

How do I know if my thread tension is correct?

Sew a test seam on two layers of fabric folded the same way as your hem. Look at the top and bottom of the seam. The stitches should look the same on both sides — the top and bobbin threads should lock in the middle of the fabric. If one side looks loose or puckered, adjust the tension dial and test again.

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

Yes, but use a ballpoint needle instead of a regular needle — ballpoint needles slide between the fibers instead of piercing them, which prevents runs and laddering. Use a stretch stitch if your machine has one, or a narrow zigzag stitch instead of a straight stitch. This lets the seam stretch with the fabric.