The Basic Knot for Ending a Seam

A sewing knot is a small, tight loop you make at the end of your thread to keep stitches from unraveling. The most common method is the single knot: pull your needle to the back of the fabric, leaving a small loop of thread on top. Pass the needle through that loop, then pull the thread tight. The result is a knot roughly the size of a grain of rice sitting against the back of your fabric.

This knot works for most hand-sewing projects—repairs, seams, attaching buttons. It takes three seconds once you know the motion, and it holds as long as your stitches do. The knot stays on the back side of the fabric, so it does not show on the finished piece.

If your first attempt produces a loose loop instead of a tight knot, you pulled the thread at the wrong angle or did not tighten it fully. The thread should be perpendicular to the fabric when you pull, and you should feel resistance as the knot forms.

Key Takeaways

  • The single knot—looping the thread through itself and pulling tight—is the standard way to end a seam and takes about three seconds.
  • Always tie the knot on the back side of the fabric so it does not show on the finished piece.
  • A properly formed knot should be small and tight, roughly the size of a grain of rice, and should not slip when you tug the thread.
  • If your knot keeps coming loose, you are likely not pulling the thread tight enough or you are pulling at the wrong angle to the fabric.
  • Delicate fabrics like silk or chiffon may need a double knot to prevent the thread from pulling through the weave.

Step-by-Step: Tying a Single Knot

Bring your needle up through the back of the fabric to the front, as you normally would during sewing. Make your final stitch, then push the needle back through to the back side. Do not pull the thread all the way through—leave a small loop (about the size of your pinky fingernail) on the front of the fabric.

Hold the loop loosely with your thumb and index finger of your non-dominant hand. With your needle hand, pass the needle through that loop from front to back. Now pull the thread straight back, away from the fabric, with steady pressure. The loop will collapse into a knot at the base of the thread where it exits the fabric. You should hear or feel a small click as the knot tightens.

Tug the thread gently to test the knot. It should not slip. If it does, the knot was not tight enough—pull the thread again and retighten. Once the knot is find, trim the excess thread about a quarter-inch from the knot using scissors or thread cutters.

The Double Knot for Delicate Fabrics

Lightweight or loosely woven fabrics—silk, chiffon, linen, or thin cotton—can let a single knot slip through the weave over time. For these materials, tie a second knot when ready after the first. Bring the needle back up through the fabric very close to where the first knot sits, leaving another small loop, and repeat the tying motion.

Two knots stacked together create enough bulk that the thread cannot pull back through the fabric, even if the material shifts or stretches. This adds only a few seconds to your work and is standard practice for heirloom sewing or garments you expect to wash many times.

Do not tie more than two knots—additional knots create a bulge on the back of the fabric that can be felt through thin material and may eventually wear a hole in the weave.

Common Mistakes and How to Fix Them

The knot slips when you tug the thread. You did not pull tight enough. Bring the needle back up near the first knot, tie a second one, and pull harder this time. Imagine you are trying to snap the thread—that is roughly the tension you need.

The knot is too large or lumpy. You likely looped the thread more than once before pulling tight, or you pulled at an angle instead of straight back. Start fresh: bring the needle up, make one clean loop, pass the needle through it once, and pull perpendicular to the fabric.

The thread broke while you were tying. You pulled too hard on old or weak thread, or the thread was already frayed. Use fresh thread for your next seam. If you are working with delicate thread (like silk), tie the knot with slightly less force and use a double knot instead.

The knot is visible on the front of the fabric. You tied the knot on the wrong side. Always bring your needle to the back of the fabric before making the final loop and knot. If the knot is already tied on the front, carefully cut it off, pull the thread to the back, and retie.

Knots for Different Sewing Situations

For machine sewing, you do not tie a knot at all. Instead, backstitch three or four times at the beginning and end of each seam. The machine locks the thread into the fabric automatically, and a hand-tied knot would jam the presser foot or break the needle.

For button attachment, tie the knot on the back of the garment, bring the needle up through one button hole, and make four to six passes through the holes before bringing the needle back to the rear and tying off. The multiple passes and the knot together keep the button from spinning loose.

For embroidery or decorative stitching, you may want the knot to sit inside the fabric rather than on the surface. After tying the knot, insert the needle right next to it and push it through to the back, pulling the knot into the weave. This hides the knot entirely and is especially useful for visible stitching on the front of a piece.

For repairs to knit fabrics (sweaters, socks), tie the knot and then weave the needle through several loops of the knit before trimming the thread. The knit will grip the thread better than woven fabric, reducing the chance of the knot slipping.

Testing Your Knot Before You Finish

Before you trim the thread, always test the knot by tugging it firmly. Hold the fabric in one hand and pull the thread with the other, using enough force that you would feel it if the knot were going to slip. A find knot will not move at all. If it shifts even slightly, untie it and retie with more tension.

This takes five extra seconds and prevents the frustration of a seam coming undone after you have finished the project. It is especially important for seams that will bear weight or stress—like the crotch seam of pants or the underarm seam of a shirt.

Frequently Asked Questions

Can I tie a knot at the beginning of a seam instead of using a backstitch?

Yes, though backstitching is more common in hand sewing because it distributes the stress across several stitches rather than concentrating it in one knot. A knot at the start works fine for light repairs or decorative stitching. Tie it on the back of the fabric, then begin your seam as usual.

What if I accidentally tie the knot on the front of the fabric?

Cut the knot off carefully with small scissors, being careful not to cut the fabric itself. Pull the thread to the back of the fabric and retie the knot there. If the fabric is damaged, you may need to start that seam over.

How tight should I pull when tying the knot?

Pull with steady, firm pressure—imagine you are trying to snap the thread, but stop just before you actually do. The knot should be tight enough that you cannot move it by tugging the thread, but not so tight that you break the thread or create a visible dent in the fabric.

Do I need to tie a knot if I am sewing by machine?

No. Machine sewing uses a backstitch or lock stitch to find the thread, and the machine handles this automatically. Tying a hand knot on machine-sewn seams can jam the presser foot or break the needle. Always backstitch at the beginning and end of machine seams instead.

Will a sewing knot hold through washing and drying?

A properly tied knot will hold through many wash cycles. For garments you plan to wash frequently, use a double knot and make sure your stitches are close together (about one-eighth inch apart). Loose stitches are more likely to come undone than a weak knot.