The basic steps to machine hem a dress

To hem a dress on a sewing machine, you measure how much fabric to remove, fold and pin the new hem line, and then sew a straight stitch around the entire bottom. The whole process takes 20 to 45 minutes depending on the dress length and how much you need to take up. You do not need special skills — a basic straight stitch is all that matters.

Start by putting on the dress and having someone mark where the hem should fall, or mark it yourself using a measuring tape and pins. The standard distance from the floor is one-half inch for most dresses, though some people prefer three-quarters of an inch. Mark all the way around the dress at the same height, then take it off and measure how much fabric sits below your mark. That measurement is what you will fold up and sew.

Fold the fabric up to your marked line, press it flat with an iron, and pin it in place every two to three inches around the entire hem. Thread your machine with thread that matches the dress fabric, set it to a straight stitch with medium length (around 2.5 on most machines), and sew slowly around the entire hem. Backstitch at the start and end to lock the thread, then remove the pins as you go or after you finish sewing.

Key Takeaways

  • Mark the correct hem height by wearing the dress and measuring from the floor, then pin the fold in place before sewing.
  • Use a straight stitch on your machine with thread that matches your dress fabric, sewing at a medium pace to keep the line even.
  • Press the fold with an iron before sewing so the fabric stays in place and your stitch line stays straight.
  • Backstitch at the beginning and end of your seam to prevent the thread from unraveling when you wear the dress.
  • Try on the dress after hemming to check the length, since small adjustments are easier to make before you cut away the extra fabric.

Measuring and marking the hem line

The most common mistake is measuring the hem height while sitting or standing unevenly. Put on the dress with the shoes you will normally wear with it, stand in front of a mirror, and have someone else use a measuring tape or ruler to mark the distance from the floor. If you are marking it yourself, use a full-length mirror and mark with pins every few inches as you walk around, checking that the height stays the same all the way around.

Once you have marked the line, take off the dress and lay it flat on a table. Measure from the marked line down to the raw edge of the fabric — that is the amount you will fold up. Write this number down so you remember it. If the dress has a curved hem (like an A-line or circle skirt), the amount of fabric to fold may vary slightly around the dress, which is normal and does not affect the final result.

Preparing the fabric and pinning

Fold the fabric up along your marked line and press it flat with a warm iron. This step matters because wrinkles will make your stitch line wavy. Fold it once so the raw edge of the fabric is hidden inside the fold, then press again. This creates a clean edge that will not fray when you wear the dress.

Pin the fold in place every two to three inches all the way around the dress. Use straight pins or quilting pins, and push them through both layers of fabric so the fold does not shift while you sew. If the hem is very long or the fabric is slippery, pin more often — every one to two inches. Check that the fold height is even all the way around by measuring from the fold to the floor in a few spots.

Threading and setting up your machine

Wind a bobbin with thread that matches your dress fabric as closely as possible. If you cannot find an exact match, choose a shade slightly darker rather than lighter, since darker thread is less visible on most fabrics. Thread the top of the machine following your machine's manual — most machines have a diagram on the side showing where the thread goes.

Set your stitch length to 2.5 or medium on the dial. This length works for most dress fabrics and creates a stitch that is strong but not so tight that it puckers the fabric. If your fabric is very thin (like chiffon or silk), use a slightly shorter stitch of 2.0. If your fabric is heavy (like denim or canvas), use 3.0. Test your stitch on a scrap of the same fabric before you start on the actual dress.

Sewing the hem

Place the dress under the presser foot so the needle will go through the fold of the hem, about one-quarter inch from the edge. Lower the presser foot, backstitch three or four stitches to lock the thread, then sew forward slowly around the entire hem. Keep the fold lined up with the edge guide on your machine so the stitch stays straight and even.

Sew all the way around until you reach the point where you started. Overlap your stitches by about one-half inch, then backstitch three or four times to lock the thread at the end. Cut the thread, remove the dress from the machine, and pull out all the pins. Press the hem again with an iron to flatten it and set the stitches.

Try on the dress and check that the hem hangs evenly and falls at the right height. If one side is longer or shorter than the other, mark the problem area, take out those stitches with a seam ripper, adjust the fold, and sew it again. Once you are happy with the length, you can trim away the extra fabric inside the fold if you want, leaving about one-half inch of fabric above the stitch line.

Common problems and how to fix them

If your stitch line is wavy, you sewed too fast or the fabric was not pressed flat before you started. Slow down and take your time — there is no prize for speed. If the fold keeps shifting while you sew, you did not pin it tightly enough. Remove the stitches, re-pin more often, and try again.

If the thread keeps breaking, your tension may be too tight. Check your machine manual for how to adjust tension, or try loosening the top tension dial by one number. If the stitch skips (you see gaps in the line), your needle may be bent or inserted backward. Replace the needle and make sure it is facing the correct direction for your machine.

If the hem puckers after you sew it, you used too short a stitch length or your tension is too tight. Remove the stitches, increase your stitch length to 3.0, and try again with slightly looser tension. Pressing the hem with an iron after sewing often removes minor puckering on its own.

Choosing thread and needle for different fabrics

Use all-purpose polyester thread for most dress fabrics — cotton, cotton blends, and most synthetics. For delicate fabrics like silk or chiffon, use a fine thread labeled for lightweight fabrics. For heavy fabrics like denim or canvas, use a heavier thread or even topstitching thread if you want the stitch to be visible.

Match your needle size to your fabric weight. A size 70/10 or 80/12 needle works for lightweight fabrics, a 90/14 for medium-weight fabrics, and a 100/16 or 110/18 for heavy fabrics. A needle that is too small will break; a needle that is too large will leave visible holes. Replace your needle after every project or every 8 to 10 hours of sewing, since a dull needle causes skipped stitches and thread breakage.

Frequently Asked Questions

Can I hem a dress without pressing it first?

You can, but the stitch line will likely be wavy and the hem will not hang as smoothly. Pressing takes five minutes and makes a real difference in how the finished hem looks. If you do not have an iron, you can use a damp cloth and a hot pan, or ask a dry cleaner to press the fold for you before you sew.

What if the dress hem is not even all the way around?

This is common on curved hems like A-line or circle skirts. Measure the distance from your marked line to the raw edge in several spots around the dress. If the distance varies by more than one-quarter inch, adjust your fold so the hem height stays even from the floor, not the fold distance. The fold distance can vary slightly without affecting how the dress looks.

How do I fix a hem if I sewed it in the wrong place?

Use a seam ripper to cut and remove the stitches. Pull out the thread carefully, then re-fold the fabric at the correct height, pin it, and sew again. Seam rippers are inexpensive and come with most sewing machines. Work slowly so you do not tear the fabric underneath the stitches.

Should I trim the extra fabric after I sew the hem?

You do not have to, but trimming makes the hem less bulky and easier to press. Leave at least one-half inch of fabric above your stitch line so the hem does not unravel. If your fabric frays easily, use pinking shears (scissors with zigzag blades) to cut the edge, or sew a zigzag stitch along the raw edge before you fold and hem.

Can I use a different stitch instead of a straight stitch?

A straight stitch is the strongest and most invisible option for a dress hem. A zigzag stitch is useful if you want to finish the raw edge at the same time, but it is less strong and more visible. Stick with a straight stitch for the best result unless you have a specific reason to use something else.