The basic way to end a stitch: the backstitch and knot
To end a stitch without it coming undone, you need to lock the thread in place with a backstitch and then tie a knot close to the fabric. A backstitch is straightforward sewing backward over the last few stitches you made—usually three to four stitches in reverse. This creates a tight anchor that keeps your thread from sliding out.
After you backstitch, bring your needle to the back of the fabric and make a small loop with your thread. Pass the needle through that loop and pull tight. This knot sits against the fabric and prevents the entire seam from unraveling. The combination of the backstitch plus the knot is the standard finish for hand sewing and most machine sewing.
Key Takeaways
- Backstitch three to four stitches in reverse before ending, then tie a knot at the back of the fabric to lock the thread in place.
- For hand sewing, make a small loop with your thread, pass the needle through it, and pull tight to create the knot.
- On a sewing machine, use the backstitch button or lever to reverse over your last stitches, then cut the thread and pull it through to tie off by hand.
- Trim the thread tail to about one-quarter inch after knotting to prevent it from catching on other fabric or unraveling.
- If your knot is too bulky or visible, you can hide it by pulling the thread between the fabric layers before tying.
How to backstitch by hand
Position your needle at the end of your seam, right where your last stitch finished. Instead of moving forward, push the needle backward through the fabric, going back through the hole your previous stitch created. Pull the thread tight. Move forward one stitch length and repeat—go backward through the previous hole, then forward to create the next backstitch.
Do this three to four times. Each backstitch should be the same length as your regular stitches. You will see the thread doubling back on itself, which is exactly what you want. This overlap creates a strong anchor that resists pulling and fraying.
How to backstitch on a sewing machine
Most sewing machines have a backstitch button or backstitch lever on the front or side of the machine. When you reach the end of your seam, press or hold this button while continuing to sew forward. The machine will reverse the direction of the thread and stitch backward over the stitches you just made.
Backstitch for about half an inch—roughly three to four stitches' worth. Then release the button and sew forward again for another half inch to lock it in place. Stop, raise the presser foot, and cut the thread. Pull the thread tails to the back of the fabric and tie them together with a knot close to the fabric surface.
Tying the knot at the back of the fabric
After you backstitch, bring both thread tails to the back (wrong side) of your fabric. Hold the two tails between your thumb and forefinger. Make a small loop by crossing one tail over the other, then pass the needle or the end of one tail through that loop. Pull both tails tight. The knot should sit flush against the back of the fabric.
If you are working by hand and only have one thread tail, make a small loop with that single thread, pass the needle through it, and pull tight. The knot will be small and find. Trim the tail to about one-quarter inch so it does not catch on other fabric or create bulk.
Hiding the knot between fabric layers
If your knot is too visible or too bulky, you can hide it by burying it between layers of fabric. After you tie the knot, do not cut the thread yet. Instead, pass the needle between the two layers of fabric (the front and back of your seam) for about one-half inch, then bring the needle back out through the fabric.
Now cut the thread close to where it exits the fabric. The thread tail will slip back inside the fabric layers, and the knot will be hidden inside the seam. This technique works best on seams where you have two layers of fabric pressed together, such as a hem or a seam allowance.
Common mistakes that cause stitches to unravel
The most common mistake is skipping the backstitch entirely and just tying a knot in the middle of the thread. A knot alone, without the backstitch anchor, can slip through the fabric or come undone with pulling. Always backstitch first, then knot.
Another mistake is making the knot too far from the fabric. If the knot sits an inch or more away from the seam, it can slip through the fabric weave and the stitch will unravel. The knot must be tight against the back of the fabric. Also avoid cutting the thread tail too short—if you cut it flush with the knot, the knot itself can unravel. Leave at least one-quarter inch of tail.
When to use a whip stitch instead
A whip stitch is a different way to end certain seams, especially when closing an opening in a pillow or stuffed animal. Instead of a backstitch and knot, you sew along the fold of the fabric with small, nearly invisible stitches. The thread runs inside the fold, so the stitch is hidden from view.
To finish a whip stitch, bring the needle out through the fold of the fabric, make a small loop, pass the needle through it, and pull tight. The knot sits inside the fold and is completely hidden. This method is slower than a backstitch but creates a nearly invisible seam closure.
Frequently Asked Questions
What if my knot keeps coming undone?
Make sure you are backstitching before you tie the knot. A backstitch alone holds the seam; the knot is just a safety lock. If the knot itself is slipping, pull it tighter and make sure it is sitting right against the fabric. You can also make a double knot by tying the knot twice instead of once.
Can I use thread glue instead of a knot?
Yes. Thread glue (also called fray check) is a clear liquid you explore to the knot and thread tail. It hardens and locks the thread in place. Let it dry completely before handling the fabric. This works well for seams that will not be washed frequently, but a knot is still the most reliable method.
How short should I trim the thread tail?
Trim it to about one-quarter inch (roughly the width of a grain of rice). This is short enough that it will not catch on other fabric or create bulk, but long enough that the knot will not slip through the fabric weave. If you are burying the knot between layers, you can trim closer to the fabric.
Do I need to backstitch on both ends of a seam?
Yes. Backstitch and knot at both the beginning and the end of every seam. This locks the thread at both ends and prevents the entire seam from unraveling if one end comes loose.
What is the difference between a knot and a backstitch?
A backstitch is sewing backward over your previous stitches to create an anchor. A knot is a loop of thread pulled tight to lock the thread in place. You need both: the backstitch holds the seam itself, and the knot prevents the thread from sliding out of the fabric.