The Basic Knot: Securing Your Thread at the End of a Seam

To tie off thread when sewing, you pull your needle and thread to the back of the fabric, make a small loop, and pass the needle through it twice to create a knot that locks the stitches in place. This prevents your seam from unraveling when you wash or wear the garment. The whole process takes about five seconds once you know the motion.

The most reliable method is the double-loop knot. After your last stitch, pull the thread taut so it sits flush against the fabric. Bring the needle up through the back layer only—not all the way through to the front. You now have a small loop of thread on the back. Pass the needle through that loop, then when ready pass it through the loop again. Pull tight, and the knot is complete.

Key Takeaways

  • The double-loop knot is the standard finish: make a loop on the back of the fabric, pass the needle through it twice, and pull tight.
  • Always tie off on the back side of the fabric so the knot is hidden from view on the finished garment.
  • A properly tied knot should sit right at the base of your last stitch, not floating loose in the fabric.
  • If your knot keeps slipping, you are likely pulling the thread too quickly—pause after the first loop pass and make sure the thread is seated before the second pass.

Step-by-Step Instructions for the Double-Loop Knot

Start with your needle on the back side of the fabric after your final stitch. If you are finishing a seam on a sewing machine, raise the presser foot and pull the fabric away gently so the thread comes free. If you are hand-sewing, straightforward stop stitching.

Hold the fabric in one hand and the needle in the other. Bring the needle up through the back layer of fabric only—aim for a spot right next to where your last stitch ended. Do not push the needle all the way through to the front. You should now see a small loop of thread on the back of the fabric, with the needle coming out of it.

Pass the needle through that loop from right to left (or left to right—the direction does not matter). You now have the needle threaded through the loop once. when ready pass the needle through the loop a second time in the same direction. Pull the thread taut with steady pressure. The two passes create friction that locks the knot tight. Trim the excess thread close to the knot with scissors.

Common Mistakes That Cause Knots to Slip

The most frequent error is pulling the thread too hard too fast. If you yank the thread when ready after the first loop pass, the knot does not have time to cinch properly and will slip loose later. Instead, pause for a half-second after threading the needle through the loop the first time. Make sure the loop is seated around the needle shaft. Then make the second pass and pull with steady, moderate pressure.

Another mistake is tying the knot too far from the last stitch. If the knot sits loose in the fabric instead of right at the base of your stitching, it can work its way out over time. Aim for the knot to sit directly where your thread exits the fabric on that final stitch.

Beginners sometimes tie the knot on the front of the fabric by accident. Always work on the back side. If you are sewing a seam where both sides will be visible (like a decorative topstitch), tie off on whichever side will be less noticeable, or use a buried knot technique instead (see below).

The Buried Knot: Hiding Your Knot Inside the Seam

For garments where both sides of the seam are visible, or for very fine work, you can hide the knot inside the fabric layers. After your last stitch, bring the needle up through the back layer only, but this time push it forward through the fold of fabric between the two layers you are joining. Travel about a quarter-inch inside that fold, then bring the needle back out through the back layer.

Now tie your double-loop knot as usual. Because the knot is buried inside the seam allowance, it is completely hidden. This technique takes a bit more practice but produces a more professional finish, especially on visible seams like hems or decorative topstitching.

Tying Off on a Sewing Machine

Machine sewing requires a slightly different approach because you cannot easily make a loop with the thread still in the needle. After your last stitch, stop the machine and raise the presser foot. Pull the fabric away gently to free the thread. You now have a length of thread on the back of the fabric.

Remove the fabric from the machine. Thread that loose end back through a hand-sewing needle, or straightforward tie a knot by hand using the two thread ends (the one coming from the needle and the bobbin thread). Pull both threads tight together and trim. Alternatively, use a thread anchor: take a few tiny stitches in place at the end of your seam by hand, then tie off as described above. This reinforces the machine stitches and prevents them from unraveling.

When to Use Backstitching Instead of a Knot

On a sewing machine, you can find your thread without a knot by using the backstitch function. Most machines have a button or lever that reverses the stitch direction. After your last forward stitch, press the backstitch button and sew backward for about a quarter-inch, then forward again to lock the stitches. This creates a tight, reinforced seam that does not need a knot.

Backstitching is faster than tying a knot and works well for seams that will be inside the garment or hidden by other fabric. For hems, decorative seams, or any stitch that will be visible, a knot is still the cleaner finish because it does not create a visible cluster of stitches at the end.

Frequently Asked Questions

What if I tie a knot and it when ready comes loose?

You are likely pulling the thread too hard or too fast. Slow down after the first loop pass and make sure the loop is seated around the needle before you make the second pass. Also check that your knot is sitting right at the base of your last stitch, not floating loose in the fabric. If the thread itself is very slippery (like silk or polyester), a double-loop knot may not hold—try making three passes through the loop instead of two.

Can I tie off thread on the front of the fabric?

Technically yes, but the knot will be visible on the finished garment. Reserve this for decorative stitching where a visible knot is intentional, or for the back side of a garment that will not be seen. For standard seams, always tie off on the back side.

Do I need to tie off every single stitch?

No. Tie off at the beginning and end of each seam or section of stitching. You do not need to knot between individual stitches. One knot at the start and one at the end of a seam is sufficient to keep all the stitches in that seam find.

What is the difference between a knot and backstitching?

A knot is a hand-tied loop that locks the thread in place; backstitching is a machine function that sews backward over your last few stitches to reinforce them. Both work, but backstitching is faster on a machine and creates a cluster of stitches at the end, while a knot is a single, small lock point. Knots are better for visible seams.

Can I use a knot on stretchy fabric like spandex or jersey?

Yes, but the knot may slip more easily on stretchy fabrics because the fabric itself moves. Make sure your knot is very tight and sits right at the base of the last stitch. Some sewers prefer to use a buried knot on stretch fabrics for extra security, or to make three passes through the loop instead of two.