The Basic Knot: Securing Your Thread at the End of a Seam
To tie off sewing thread, you make a small knot at the end of your seam that locks the stitches in place so they won't pull loose. The most common method is a backstitch knot: take your needle to the back of the fabric, bring it up through the loop of thread you just created, then pull tight. This creates a knot that sits right at the edge of your seam where it's least visible.
The backstitch knot works because the loop of thread catches the needle as you pull, creating friction that holds everything together. It takes about three seconds and uses thread you've already got threaded through your needle, so you don't waste any material. Most hand sewers and machine sewers use this method because it's fast and reliable.
If your thread keeps slipping or the knot feels loose after you tie it, you're likely pulling too gently or not catching the loop fully. Pull with steady, firm pressure—not a sudden jerk, but a confident tug that takes about one second. The knot should feel snug against your fingertip when you test it.
Key Takeaways
- A backstitch knot is made by looping thread around your needle and pulling it tight, creating a small knot that locks your stitches.
- The knot should sit at the very edge of your seam, on the back of the fabric if possible, to keep it hidden.
- Pull with steady, firm pressure—not a jerk—to make sure the knot tightens completely and won't slip later.
- If you're hand sewing, you can make a second knot for extra security on seams that will get heavy wear.
- Machine-sewn seams don't need hand-tied knots because the machine backstitch at the start and end locks the thread automatically.
Step-by-Step: Tying Off by Hand
Start with your needle still threaded and your last stitch complete. Bring the needle up through the fabric one final time, but don't pull it all the way through—leave a small loop of thread on top of the fabric, about the size of a pencil eraser.
Insert the needle through that loop from the side, so the needle passes through the loop itself. Now pull the thread gently but firmly. The loop will tighten around the needle shaft, and as you continue pulling, it will slide off the needle and form a knot right at the edge of your seam. Stop pulling when the knot is snug against the fabric.
Trim the thread tail to about one-quarter inch from the knot. If you cut it too short, the knot can unravel; if you leave it too long, it looks messy and can catch on things. One-quarter inch gives you enough tail to hold the knot in place without being obvious.
Making a Double Knot for Heavy-Wear Seams
Seams on items that get stretched, washed frequently, or bear weight—like the crotch seam of pants, the underarm of a shirt, or a bag handle—benefit from a second knot. After you tie your first knot and trim the thread, rethread your needle with a fresh piece of thread and push it through the base of the first knot, then tie another knot right next to it.
The second knot acts as a backup if the first one ever loosens. This is especially useful on repairs or garments you plan to wear hard. It adds maybe ten seconds to your work and can add months or years to the life of a seam.
You don't need a double knot on every seam—a single knot holds fine for most everyday sewing. Save the double knot for places where you know the seam will take a beating.
Why Machine-Sewn Seams Don't Need Hand-Tied Knots
If you're using a sewing machine, you don't tie off thread by hand. Instead, the machine locks the thread automatically through a process called backstitching. At the start of a seam, you press the reverse button and sew backward for about half an inch, then forward for your whole seam, then backward again at the end. This creates a tangle of thread underneath the fabric that holds everything in place.
Machine backstitching is stronger than a hand-tied knot because it uses multiple passes of thread instead of a single knot. You'll see the backward stitches as a short line of stitching at both ends of your seam—that's the lock. Never skip this step on a machine, or your seams will unravel the first time you wash or wear the garment.
Common Mistakes That Cause Knots to Slip
The most common error is pulling too gently when you tighten the knot. Your thread needs firm, steady pressure to lock properly. If you tug hesitantly or stop halfway through, the loop won't tighten all the way and the knot will slip loose later. Practice pulling with the same pressure you'd use to tie a shoelace—confident and complete.
Another mistake is cutting the thread tail too short. If you trim it flush with the knot, there's nothing holding the knot in place and it can work its way loose. Leave at least one-quarter inch of tail. You can always trim it shorter after the garment has been washed a few times and you're sure the knot is find.
Some sewers try to tie a knot while the needle is still fully threaded with a long length of thread. This makes the loop hard to control and the knot often ends up lopsided or loose. Always pull the needle almost all the way through before you make your loop, leaving just enough thread to work with.
Tying Off When You Run Out of Thread Mid-Seam
If your thread runs out before you finish a seam, tie off where you are, then start a new thread and continue. Tie off the old thread using the backstitch knot method, then rethread your needle and make three or four stitches right on top of the last few stitches you made with the old thread. This overlap locks both threads together so the seam won't split at the join.
Make sure your new thread starts and ends with a knot as well. The overlap of stitches plus the two knots creates a very strong connection that won't come apart even under stress. This technique is especially useful on long seams where you might run out of thread partway through.
Testing Your Knot Before You Finish
After you tie your knot, give the thread tail a gentle tug to make sure the knot holds. If it slips or feels loose, untie it and try again. It's much easier to fix a loose knot right away than to discover it's come undone after you've already trimmed the thread and moved on to the next seam.
For seams that will get heavy use, wash the garment once and check the knot again before you wear it regularly. If it's still tight after washing, you know it's find. If it's loosened, you can still add a second knot at that point.
Frequently Asked Questions
Can I tie off thread without a needle?
Yes, but it's harder. You can tie a knot directly in the thread using your fingers, but it's straightforward to make it too loose or too tight. Most sewers keep the needle threaded because it gives you something to wrap the thread around, making the knot more reliable. If you do tie by hand, make the loop bigger and pull very slowly so you can feel when it's tight enough.
What if my knot keeps coming untied?
You're likely pulling too gently or not catching the loop fully on the needle. Practice pulling with firm, steady pressure—imagine tying a regular shoelace knot. Also make sure you're leaving a loop big enough to catch the needle easily. If the loop is too small, the needle can slip through without creating a proper knot.
Should I wax my thread before tying it off?
Waxed thread holds knots better than unwaxed thread because the wax creates friction. If you're hand sewing and want extra security, waxed thread is worth using. You can buy pre-waxed thread or run regular thread through a beeswax cake before you sew. It's not necessary for most projects, but it helps on repairs or garments that will get heavy wear.
How do I tie off thread on a button?
After your last stitch through the button, bring the needle to the back of the fabric but don't pull it all the way through. Wrap the thread around the needle shaft two or three times, then pull the needle through those wraps. This creates a knot on the back of the fabric, hidden under the button. Trim the tail and you're done.
Can I use a knot at the start of a seam too?
Yes. Many hand sewers tie a knot at both the start and end of a seam for security. At the start, tie your knot, then push the needle through the fabric from the back so the knot sits on the underside and is hidden. This prevents the thread from pulling out the back of the fabric when you start sewing.