The Basic Stitch for a Pants Hem

A hand-sewn hem on pants uses a slip stitch (also called a ladder stitch or invisible stitch), which hides the thread inside the fold of fabric so the seam is nearly invisible from the outside. The stitch works by running your needle through the fold of the hem, then catching just two or three threads of the pant leg above it, then back into the fold—creating a ladder pattern inside the hem that pulls tight and closes the gap.

This method takes about 20 to 40 minutes per pant leg, depending on the hem length and your speed. You will need a needle, thread that matches your pants, scissors, pins, and a measuring tape. The slip stitch is the standard choice for dress pants, casual pants, and jeans because it holds through washing and wearing without puckering the fabric.

Key Takeaways

  • Measure and pin the hem at the correct length before you sew—try the pants on and mark where the fabric should end, usually about half an inch above your shoe.
  • Fold the raw edge of the fabric up into the hem about a quarter inch, then fold the hem itself up to your marked line and pin it in place all the way around.
  • Thread your needle with a single strand about 18 inches long, knot one end, and start the slip stitch by pushing the needle through the fold so the knot stays hidden inside.
  • The slip stitch alternates between running the needle through the fold of the hem and catching just two or three threads of the pant leg fabric above it, pulling snug every few stitches.
  • Sew all the way around the pant leg, tie off the thread inside the fold, and trim the excess—the seam should be invisible from the outside when you try the pants on.

Measure and Mark Your Hem Length

Put on the pants with the shoes you will normally wear with them. Have someone help you, or stand in front of a mirror and use a measuring tape. The hem should rest about half an inch above the top of your shoe, or just barely touching the shoe in the back. Mark this line with a fabric pencil, tailor's chalk, or pins placed every 2 to 3 inches around the pant leg.

If you are hemming both legs, measure from the floor up to your mark on one leg, then measure that same distance on the other leg—this ensures both hems are the same length even if your legs are slightly different lengths. Write down the measurement so you remember it for the second leg.

Try the pants on one more time to confirm the length is correct before you cut or fold anything. Once you start sewing, it is much harder to undo than to get the length right the first time.

Prepare the Hem for Sewing

Try on the pants one last time and fold the pant leg up to your marked line. Pin the fold in place every 2 inches all the way around the leg. The fold should be smooth and even—no twists or bunches.

Now look at the raw edge of the fabric (the cut edge at the bottom of the pant leg). If it is frayed or rough, fold it up about a quarter inch toward the inside of the pant leg and pin that fold in place too. This creates a finished edge that will not fray when you wash the pants. If the fabric is a knit or stretchy material, you may want to fold the raw edge up a half inch instead to give yourself more fabric to catch with your needle.

Once everything is pinned, try the pants on again to make sure the hem still looks right and hangs straight. The pins should hold the fold firmly in place without puckering the fabric.

Thread Your Needle and Start the Slip Stitch

Cut a piece of thread about 18 inches long—longer than that and it tangles easily, shorter and you will have to tie on a new thread before you finish one side. Thread it through your needle and tie a knot at one end. Use a needle size that feels comfortable in your hand; a size 7 or 8 is standard for most pants fabrics.

Start sewing at a seam on the inside of the pant leg—the side seam or inseam works well because the stitches will be hidden there. Push the needle through the fold of the hem from inside, so the knot stays hidden in the fold. Bring the needle out about a quarter inch along the fold. You are now ready to begin the slip stitch.

Execute the Slip Stitch in a Steady Pattern

The slip stitch alternates between two moves: one stitch inside the fold, one stitch in the pant leg fabric above the fold. Here is the exact sequence: From inside the fold, push your needle straight across into the pant leg fabric above the fold, catching only the top 2 or 3 threads of the fabric—do not go all the way through to the outside. Slide the needle about a quarter inch to a half inch along inside those top threads, then bring the needle back out through the pant leg fabric and into the fold.

Now push the needle straight across inside the fold, sliding it about a quarter inch to a half inch along the fold, and bring it back out. You have now completed one full stitch. The pattern looks like a ladder when you look at it from inside the hem: one rung in the fold, one rung in the pant leg, one rung in the fold, and so on.

Pull the thread snug every 3 or 4 stitches—not so tight that you pucker the fabric, but tight enough that the fold closes and the stitches disappear. If you pull too hard, the fabric will bunch and the hem will look wavy. If you do not pull tight enough, the hem will gap open and the stitches will show.

Sew Around the Entire Pant Leg

Continue the slip stitch all the way around the pant leg, keeping your stitches about a quarter inch to a half inch apart. As you work, the hem should fold up smoothly and the stitches should stay hidden inside the fold. Check the outside of the pant leg every 2 or 3 inches—you should see almost no thread or stitches from the outside.

When you get close to where you started, overlap your stitches by about a quarter inch to lock the seam. Bring your needle out through the fold, then push it back through the first stitch you made to anchor the end. Tie a knot inside the fold by looping the thread around your needle twice and pulling it tight, then push the needle through the fold one more time and trim the excess thread close to the fabric.

Try the pants on and check the hem from the outside. It should look smooth and even, with no visible stitches or gaps. If you see a gap or loose spot, you can go back and add a few more stitches in that area.

Common Mistakes and How to Avoid Them

Stitches showing on the outside: This happens when you catch too many threads of the pant leg fabric or when you pull the thread too tight. Catch only 2 or 3 threads, and pull snug but not tight. If the stitches are already visible, you can carefully pull them out and re-sew that section.

Hem puckering or bunching: This usually means you pulled the thread too tight or the fabric was not pinned smoothly before you started. Unpin and re-pin the hem, making sure the fold is straight and even, then sew again with a lighter hand on the thread tension.

Hem coming loose after washing: This happens when the stitches are too far apart or when you did not tie off the thread securely at the end. Space your stitches no more than half an inch apart, and tie your knot inside the fold where it will not come undone.

Needle breaking or bending: You are likely pushing too hard into thick fabric. Use a needle one size larger, or try a needle designed for denim if you are hemming jeans. Push the needle through with steady pressure rather than force.

Frequently Asked Questions

Can I use a sewing machine instead of hand sewing?

Yes, a sewing machine is faster and the stitches are stronger, but a hand-sewn hem is less visible and more flexible, which some people prefer for dress pants. A machine hem works well for jeans and casual pants. If you use a machine, use a thread that matches your pants and a stitch length of about 2 to 2.5 millimeters.

What if my pants are too long and I need to cut the fabric?

Measure from your marked hem line down to the raw edge. If there is more than 2 inches of fabric, you can trim it to about 1.5 inches above your marked line. This gives you enough fabric to fold up for the hem without making it too bulky. Use sharp scissors and cut in a straight line all the way around the pant leg.

How do I sew a hem on stretchy or knit pants?

Knit fabrics need a bit more fabric in the hem to prevent the stitches from pulling through. Fold the raw edge up a half inch instead of a quarter inch, and use a slightly longer stitch—about half an inch instead of a quarter inch. You can also use a ballpoint needle, which is designed for knit fabrics and will not split the threads.

Do I have to match the thread color exactly?

Matching the thread color as closely as possible makes the stitches invisible from the outside. If you cannot find an exact match, choose a color slightly darker than the fabric rather than lighter—darker thread is less noticeable. For patterned fabric, match the dominant color.

How long does a hand-sewn hem last?

A properly sewn hem lasts through many washings and wearings—usually as long as the pants themselves. The slip stitch is strong because it distributes the stress across many small stitches rather than one seam. If a stitch does come loose, you can add a few stitches in that spot without taking out the whole hem.