The basic steps for a machine-sewn hem
A sewing machine hem on a dress takes about 30 minutes once you have marked the length. You need the dress on a person (or a dress form), a measuring tape, pins, scissors, and thread that matches the fabric. The process is: try on the dress, mark where it should end, fold the fabric up to that line, pin it in place, sew along the fold with a straight stitch, and trim the excess fabric inside the hem.
The key difference between a hand-sewn and machine-sewn hem is speed and strength. A machine stitch holds better under wear and washing, especially on everyday dresses. The trade-off is that machine stitches are visible from the inside, and if you make a mistake with the length, unpicking takes longer than hand-sewing would.
Key Takeaways
- Mark the hem length with the dress on the person wearing it, standing in the shoes they will wear with that dress.
- Fold the fabric up to your marked line, pin it every 2 to 3 inches, and press with an iron before sewing to keep the fold straight.
- Use a straight stitch on your machine with matching thread, sewing about 1/4 inch below the fold so the stitch catches both layers.
- Trim the raw edge inside the hem to 1/2 inch, then finish that edge with a zigzag stitch or pinking shears to stop fraying.
Measuring and marking the hem length
Put the dress on the person who will wear it, and have them stand in the shoes they plan to wear with that dress. Shoes change the angle of your leg and foot, which changes where the hem should fall. If the dress will be worn with flats one day and heels another, pick one and stick with it for the hem.
Use a measuring tape or a hem gauge (a small ruler with a sliding marker) to measure up from the floor to where you want the hem to end. A typical dress hem sits 1/2 inch to 1 inch above the floor when standing. Mark this line all the way around the dress with tailor's chalk, a fabric pencil, or pins. Step back and look at the line — it should be level all the way around, not higher on one side.
If you do not have a second person to help, try on the dress yourself, use a full-length mirror, and mark the line while standing. You can also pin the dress to the length you want, try it on, and adjust before you commit to cutting.
Pinning and pressing the fold
Fold the fabric up along your marked line so the wrong side (the inside) of the dress faces out. The fold should be crisp and even. Pin the fold in place every 2 to 3 inches all the way around, pushing the pins through both layers so they hold the fold steady.
Press the fold with an iron on a low to medium heat setting — check your fabric first to make sure heat will not damage it. A pressed fold is much easier to sew in a straight line than an unpressed one. Let the fabric cool for a moment before you unpin it and move it to the sewing machine.
If your dress has a lining, you will need to separate the lining from the outer fabric at the hem. Fold and pin only the outer layer, leaving the lining loose. You will sew the lining separately after the outer hem is done.
Sewing the hem with a straight stitch
Thread your machine with thread that matches the dress fabric as closely as you can. If you cannot find an exact match, choose a shade slightly darker than the fabric — it will be less visible than a lighter shade. Wind a bobbin with the same thread.
Set your machine to a straight stitch with a stitch length of 2 to 2.5 millimeters. This length is small enough to hold the fabric securely but large enough that you can unpick it if you need to. Test the stitch on a scrap of the same fabric first to make sure the tension is even and the thread is not bunching.
Position the dress under the presser foot so the needle will sew about 1/4 inch below the fold. This distance lets the stitch catch both the fold and the layer underneath. Sew slowly and steadily all the way around the dress, removing pins as you approach them. Backstitch at the beginning and end to lock the thread.
Trimming and finishing the raw edge
Once the stitch is complete, trim the raw edge of the fabric inside the hem down to about 1/2 inch from the stitch line. Use sharp fabric scissors and cut as close to the stitch as you safely can without cutting the thread itself.
Finish the raw edge so it does not fray during washing. The easiest method is a zigzag stitch: set your machine to a zigzag with a width of 2 to 3 millimeters and a length of 2 millimeters, then sew along the raw edge. The zigzag will wrap around the edge and seal it. Alternatively, use pinking shears (scissors with a sawtooth blade) to cut the edge in a zigzag pattern, which also stops fraying.
If your dress has a lining, fold and sew the lining hem separately, making it about 1/2 inch shorter than the outer hem so it does not show below the dress.
Fixing common hemming mistakes
If your hem is uneven after sewing, you can unpick it and try again. Use a seam ripper (a small tool with a curved blade) to cut and remove the stitches. Pull gently so you do not tear the fabric. Once the stitches are out, press the fabric flat again, re-mark the line if needed, and sew a new hem.
If the stitch puckers or bunches, the tension on your machine may be too tight. Loosen the top tension slightly and test on a scrap before sewing the dress again. Puckering can also happen if you are sewing too fast — slow down and let the machine do the work.
If you sewed the hem too short or too long, you will need to unpick it and start over. This is why measuring twice and trying on the dress before you sew is worth the extra time. A dress that is hemmed 1/4 inch too short is much harder to fix than one that is 1/4 inch too long.
Choosing between a machine hem and other methods
A machine-sewn hem is the fastest and strongest option for everyday dresses, especially knit fabrics that move a lot. It works well on cotton, linen, and most blends. A hand-sewn hem is less visible from the inside and is better for delicate fabrics or heirloom pieces, but it takes longer and is not as durable.
Hemming tape (a fusible web you iron on) requires no sewing at all, but it can feel stiff and may not hold through many washings. It works best on lightweight fabrics and for temporary hems. If you are hemming a dress you plan to wear often, a machine stitch is the better choice.
Some fabrics, like stretchy knits, work better with a ballpoint needle and a stretch stitch on your machine instead of a straight stitch. Check your fabric content and your machine manual to see what stitch your machine recommends.
Frequently Asked Questions
What thread color should I use if my fabric is multicolored?
Choose a thread that matches the dominant color or the color of the hem area itself. If the hem will be hidden inside a shoe or under another layer, an exact match matters less. Test the thread on a hidden part of the dress first to see how visible it is.
Can I hem a dress with a stretch fabric on a regular sewing machine?
Yes, but use a ballpoint needle and a stretch stitch if your machine has one. A regular needle can skip stitches on stretchy fabric, and a straight stitch may break when the fabric moves. A stretch stitch is designed to flex with the fabric.
How do I know if my hem is the right length?
The dress should sit 1/2 inch to 1 inch above the floor when you stand in the shoes you will wear with it. The hem should be level all the way around — use a mirror to check the sides and back. If it looks even and feels comfortable, the length is right.
What if I sewed the hem and it is still puckering?
Puckering usually means the tension is too tight or you sewed too fast. Loosen the top tension dial by one number and test on a scrap. If that does not work, unpick the hem and try again with a slower speed. Let the machine feed the fabric instead of pushing it.
Do I need to press the hem after sewing?
Yes. Press the finished hem with an iron on a low to medium heat to flatten it and set the stitch. This makes the hem look neater and helps it hold its shape through washing. Use a pressing cloth between the iron and the fabric if you are worried about shine or damage.