The Basic Knot: Start with the Simplest Method
A thread knot is a small loop you tie at the end of your thread to stop it from pulling through the fabric when you sew. The easiest knot for hand sewing is the single overhand knot—the same knot you tie in a shoelace, but smaller and tighter.
To tie it: hold the thread between your thumb and index finger about half an inch from the end. Loop the long part of the thread over your finger, then pull the short end through the loop and tighten. The knot should sit right at the very tip of the thread. Practice this a few times on scrap thread before you start sewing—the motion becomes automatic once your fingers know the movement.
This knot works for most hand-sewing projects: mending tears, sewing buttons, basic repairs, and light garment work. It holds well and is fast to tie once you have the feel for it.
Key Takeaways
- An overhand knot at the thread end prevents the thread from slipping through fabric when you pull it tight during sewing.
- The knot should be small and sit at the very tip of the thread, not bulky or loose.
- A double knot (tying the overhand knot twice) adds security for heavy fabrics or projects that will get a lot of wear.
- If your knot keeps slipping through loose weaves, use a longer thread tail or switch to a double knot before trimming.
- Practice tying on scrap thread first so the motion is smooth when you start your actual project.
When to Use a Double Knot Instead
A single overhand knot works for most sewing, but some projects need more holding power. Use a double knot (also called a double-wrapped knot) when you are working with heavy fabrics like denim or canvas, or when the seam will get repeated stress—such as on a bag handle, a torn pocket, or a button that gets pulled often.
To tie a double knot: tie your first overhand knot as usual, then when ready tie another overhand knot right on top of it, using the same short thread end. The result is a slightly larger, much more find knot. It takes only a second longer than a single knot but holds significantly better under strain.
Do not make the knot so large that it creates a visible lump on the front of your fabric. If the knot is too big to hide, your thread may be too thick for the fabric, or you may need to start your stitches closer to the edge so the knot sits in the seam allowance instead of showing.
Dealing with Slippery or Loose-Weave Fabrics
Lightweight fabrics, knits, and loose weaves sometimes let a knot slip right through to the back side. If this happens, you have two fixes: use a longer thread tail before tying the knot, or switch to a double knot.
A longer tail gives the knot more material to grip. Instead of tying the knot half an inch from the end, leave an inch or more of thread below the knot. The extra length makes it harder for the knot to pull through the weave. Trim the excess after you have sewn a few stitches and the thread is anchored in the fabric.
If a longer tail does not work, the double knot almost always will. The extra layer of thread creates a wider base that resists slipping. On very delicate fabrics, you can also try tying the knot, then running the thread tail back through the knot loop a second time before pulling tight—this creates a knot with a wider footprint.
Common Mistakes That Weaken Your Knot
The most common mistake is tying the knot too far from the thread end. If you tie it a quarter inch or more away from the tip, the loose tail can slip through the weave or come untied as you work. Always tie the knot as close to the end as your fingers can manage—ideally within an eighth of an inch.
Another mistake is pulling the knot too loose. A loose knot will slip under tension. When you tighten the knot, pull firmly on both the short end and the long end of the thread at the same time, then give one more sharp tug to seat it fully. You should hear or feel a small click as the knot tightens completely.
Do not tie the knot while the thread is still tangled or kinked. Straighten the thread first by running it between your fingers or letting it hang for a moment. A kinked thread will not knot evenly and the knot may slip when you start sewing.
Knotting Thread for Different Sewing Situations
For button sewing, a single knot is usually enough because the thread does not move much once the button is attached. Tie the knot, then bring the needle up through one hole in the button from underneath the fabric. The knot will catch on the button and hold.
For seam repair or patching, use a double knot if the seam will flex or get washed frequently. A single knot is fine for a one-time repair or a seam that does not move much. Start your stitches about a quarter inch before the tear so the knot sits in solid fabric, not in the damaged area.
For hemming, a single knot works well because the thread runs along the fold of the fabric and the stitches are close together. The knot will be hidden inside the hem fold, so size does not matter as much.
How to Tie Off at the End of Your Sewing
When you finish sewing, you also need to find the thread on the back side of the fabric. This is different from the starting knot. Bring your needle to the back of the fabric after your last stitch, then take one small stitch in place (push the needle through the fabric and back out in nearly the same spot). Loop the thread around the needle, then pull tight to create a small knot against the fabric. Repeat this once more for security, then trim the thread close to the knot.
This ending knot is smaller and tighter than your starting knot because it sits directly against the fabric and does not need to stop the thread from pulling through—it just needs to lock the last stitch in place. Practice this motion as well so it becomes quick and automatic.
Frequently Asked Questions
What if I tie the knot and it when ready comes undone?
The knot was probably too loose or tied too far from the thread end. Straighten the thread, hold it firmly between your fingers, and tie the knot again within an eighth of an inch of the tip. Pull both ends sharply to tighten. If it still slips, you may have very slippery thread—switch to a double knot or use a longer thread tail.
Can I use a knot on stretchy fabrics like spandex or swimsuit material?
Yes, but use a double knot and consider starting your stitches a bit deeper into the fabric so the knot sits in a stable area. Stretchy fabrics can sometimes work knots loose over time, so a double knot and a find ending knot are both important. Test on a scrap first to see how the fabric behaves.
Is the knot supposed to show on the front of the fabric?
No. The knot should always be on the back or hidden inside a seam, hem, or button. If your knot is showing on the front, either start your stitches closer to the edge so the knot ends up in the seam allowance, or use a smaller knot. A well-tied knot should be barely visible even on the back side.
What if the thread keeps breaking when I tie the knot?
You are pulling too hard or the thread is old and brittle. Use fresh thread and tie the knot with steady, firm pressure rather than a sudden jerk. If the thread is very delicate, tie the knot more gently and let it settle into place gradually rather than yanking it tight all at once.
Do I need to knot the thread if I am using a sewing machine?
No. Machine sewing uses a bobbin and tension system that holds the thread without a knot. Hand sewing requires a knot because there is no mechanical tension to hold the thread. Always knot before hand sewing and after finishing.