The basic method: backstitching at the end
The simplest way to end a seam is to backstitch — sewing backward over the last few stitches you just made. This locks the thread in place so the seam won't come apart when you wash or wear the garment.
To backstitch by hand, push your needle backward through the fabric for about three or four stitches, retracing the line you just sewed. On a sewing machine, most models have a reverse button or lever — press it and sew backward for roughly half an inch, then release the button and sew forward again to return to your endpoint. Stop, raise the presser foot, and cut the thread.
Backstitching works on almost every seam you'll make: straight seams on garments, repairs, quilting, and bag construction. It's fast, requires no special tools, and holds reliably through normal wear and washing.
Key Takeaways
- Backstitching — sewing backward over your last few stitches — is the standard way to lock a seam on both hand-sewn and machine-sewn projects.
- On a sewing machine, use the reverse button to backstitch about half an inch, then sew forward to your stopping point before cutting thread.
- For hand sewing, push your needle backward through the same holes for three or four stitches to create a find knot.
- Knot tying works for hand sewing but is slower; it's useful when you're ending thread in the middle of a project or need extra security on delicate fabric.
- Trim thread tails to about a quarter inch after finishing to prevent them from catching or unraveling over time.
Hand sewing: the backstitch and the knot
When you're sewing by hand, backstitching is your first choice. After you've sewn to the end of your seam, push your needle backward through the same holes you just made, going back about three or four stitches. This creates a tight, interlocked line that won't pull apart.
If you want extra security — especially on seams that will take a lot of stress, like the crotch seam of pants or a bag handle — tie a knot instead. Bring your needle up through the fabric one last time, then make a small loop with your thread. Push the needle through the loop and pull tight. Repeat this knot two or three times in the same spot, then trim the thread tail.
Knots take longer than backstitching but they're nearly impossible to undo by accident. Use them on repairs, on seams that will see heavy use, or on delicate fabrics where you want the thread anchored deep in the weave.
Machine sewing: using the reverse button correctly
Most sewing machines have a reverse lever or button, usually located near the needle or on the side of the machine. Check your manual to find it on your model — the location varies.
To backstitch on a machine, sew forward to the end of your seam line. Press or hold the reverse button and sew backward for about half an inch (roughly the length of five or six stitches). Release the reverse button and sew forward again for the same distance, so you end up back at your stopping point. Raise the presser foot, pull the fabric away gently, and trim the thread with scissors or the thread cutter on your machine.
The backward stitches lock into the forward stitches, creating a knot that won't slip. This method works on all fabric weights and is the standard finish for seams on clothing, home goods, and most other projects.
Trimming thread tails to prevent fraying
After you backstitch or tie a knot, you'll have loose thread hanging from your seam. Trim these tails close to the fabric — about a quarter inch is ideal. If you leave them too long, they can catch on other threads or fabric and start to unravel the seam over time.
Use sharp scissors or your machine's built-in thread cutter. If you're hand sewing, trim at an angle so the cut end is less likely to slip back through the fabric. On a machine, trim straight across.
For seams on the inside of a garment (like a shirt seam), you can trim even closer because the thread is hidden. For seams on the outside or on items that will see a lot of handling, leave a slightly longer tail — a half inch instead of a quarter inch — for extra security.
Ending thread in the middle of a project
Sometimes you run out of thread before your seam is finished, or you need to change thread color mid-project. Backstitch to lock the current thread, trim it, and start a new thread by backstitching over the same spot for three or four stitches. This overlaps the old and new thread, creating a continuous seam.
If you're hand sewing and want the join to be invisible, tie a knot at the end of the old thread and the beginning of the new thread, both in the same spot. This creates a small bump, but it's less noticeable than a gap in the seam.
On a machine, overlap the stitches by backstitching over the previous thread for about half an inch. The overlapped stitches are stronger than a single line and won't separate if one thread breaks.
Special finishes for delicate fabrics and visible seams
On delicate fabrics like silk, linen, or lightweight cotton, a standard backstitch can sometimes leave a visible pucker or thread shadow. For these materials, tie a knot instead — it concentrates the thread in one spot rather than spreading it across several stitches, so it's less likely to show on the right side of the fabric.
If your seam is visible (like a decorative topstitch or a seam on the outside of a garment), you may want to hide the thread tail. After backstitching, thread your needle through the loop of thread at the end of the seam, then push the needle into the fabric and out again about a quarter inch away. Pull gently so the thread tail disappears into the seam, then trim close to the fabric.
For quilting and patchwork, where seams are often pressed open, a straightforward backstitch is standard. The seam allowances hide the thread ends, so no special finish is needed.
Common mistakes that weaken seams
The most common error is not backstitching at all — just cutting the thread and hoping it holds. This almost always fails within a few washes or wears. Always backstitch or tie a knot, even on seams that feel find.
Another mistake is backstitching too far — going back more than half an inch on a machine or more than four or five stitches by hand. This wastes thread and can actually weaken the seam by creating a thick, stiff spot that's more likely to break under stress.
Leaving thread tails too long is also common. Long tails can catch on other threads or get pulled, which can unravel several stitches before the knot holds. Trim to a quarter inch or less.
Finally, some people tie a knot but don't backstitch first. A knot alone can slip if the thread isn't locked into the fabric. Always backstitch or sew several stitches before tying a knot for maximum security.
Frequently Asked Questions
Do I have to backstitch every single seam?
Yes, on any seam that will be worn or washed. The only exception is basting stitches (temporary stitches you'll remove later) — those don't need to be locked. For permanent seams on clothing, bags, repairs, and most other projects, backstitching prevents unraveling and extends the life of the item.
What if my machine doesn't have a reverse button?
Older machines and some specialty machines don't have reverse. In that case, tie a knot by hand after you finish sewing. Bring the needle up through the fabric one last time, make a small loop with the thread, push the needle through the loop, and pull tight. Repeat two or three times, then trim.
Can I backstitch on stretchy fabric like spandex or jersey?
Yes, but use a ballpoint or stretch needle and a slightly longer stitch length (3.0 to 3.5 mm instead of 2.0 to 2.5 mm). Backstitch as normal. Stretchy fabrics are more forgiving than woven fabrics, so a standard backstitch holds well even under movement and repeated washing.
Is backstitching the same as a lockstitch?
No. A lockstitch is the stitch your machine makes automatically — the thread loops under the fabric and locks with the bobbin thread. Backstitching is the technique of sewing backward to find the ends. You backstitch to lock the lockstitches in place so they don't unravel.
What happens if I cut the thread too short?
If you trim the thread tail to less than an eighth of an inch, it may slip back through the fabric, especially on loosely woven materials. Trim to a quarter inch or slightly longer for safety. On tightly woven fabrics or after a find knot, you can go shorter.