What a Slip Stitch Is and When to Use It
A slip stitch is a hand-sewing technique that hides the thread inside the fold of fabric, making the seam nearly invisible from the outside. The needle travels through the fold of one piece of fabric, then slips directly into the fold of the opposite piece, catching only a thread or two of fabric before emerging back into the fold. This creates a closure that looks like the fabric sealed itself.
Use a slip stitch to close openings after you have stuffed a pillow, sewn a seam on a garment, or attached a patch. It works best on straight edges and folds where you can hide the thread completely. The stitch is slower than a running stitch but worth the time because the seam disappears once you are done.
Key Takeaways
- Thread your needle and knot the end, then start inside a fold of fabric so the knot hides in the crease.
- Slide the needle through the fold for about one-quarter inch, then push it straight across into the opposite fold and slide it forward the same distance.
- Pull the thread snug every few stitches so the fabric edges close together without puckering.
- End by making two small stitches in the same spot inside the fold, then trim the thread close to the fabric.
Thread, Needle, and Fabric Preparation
Use a thread that matches your fabric color as closely as possible—even a slip stitch shows a tiny bit of thread, and a mismatch will be visible. A single strand of thread works best; if your thread is thick, separate it into thinner plies. Cut a length about 18 inches long so you have enough to work with but not so much that it tangles.
Choose a needle small enough to pass through your fabric without leaving holes, but large enough that the thread slides through easily. A size 8 or 9 sharps needle works for most fabrics. Knot the end of the thread by wrapping it once around your finger, rolling the loop off, and pulling tight.
Before you start, press the opening flat with an iron so the edges are crisp and straight. If the edges are frayed, trim them or fold them under slightly and press again. The neater your starting edges, the neater your finished seam.
Starting the Slip Stitch Inside the Fold
Insert your needle into the fold of fabric on one side of the opening, about half an inch from where you want to start stitching. Push the needle through the fold—not through both layers, but through the crease itself. Slide the needle forward inside the fold for about half an inch, then bring it back out. This hides your starting knot inside the fold where it will not show.
Pull the thread snug but not tight enough to pucker the fabric. You should feel the thread sitting inside the fold, not pulling the edges together yet. This first stitch anchors your thread and positions it correctly for the rest of the seam.
The Basic Slip Stitch Motion: Fold to Fold
Bring your needle out of the fold on the first side of the opening. Now push the needle straight across the opening into the fold on the opposite side, directly across from where you just came out. The needle should enter the fold cleanly without catching the main body of the fabric.
Once the needle is inside the opposite fold, slide it forward about one-quarter inch inside that fold, then bring it back out. You have now completed one stitch: you went from the first fold, across the opening, into the second fold, and back out. The thread is now hidden inside the second fold.
Repeat this motion: push the needle straight across the opening into the first fold again, slide it forward one-quarter inch, and bring it back out. Continue alternating from fold to fold. Each stitch should be about one-quarter inch long, and the space between stitches should be roughly the same size.
Keeping Tension Even and Closing the Gap
After every three or four stitches, gently pull the thread to draw the two edges of the opening together. Do not yank—pull just enough to close the gap without creating wrinkles or puckers in the fabric. If you pull too hard, the fabric will bunch up and the seam will look uneven. If you do not pull hard enough, the opening will not close completely.
The key is to pull perpendicular to the seam, not along it. Imagine the thread as a drawstring: you are tightening it to bring the edges together, not sliding it along the seam. After you pull, take another stitch or two before pulling again.
As you near the end of the opening, check that the edges are meeting evenly. If one side is ahead of the other, adjust your stitch length slightly on the next few stitches to even them out. A slip stitch that closes unevenly will look crooked even though the thread is hidden.
Finishing and Securing the Thread
When you reach the end of the opening, bring your needle out of the fold one last time. Make two small stitches in the same spot inside the fold—push the needle in and out of the fold twice without moving forward. This creates a knot that anchors the thread so it will not unravel.
Slide the needle inside the fold for about half an inch, then bring it back out and trim the thread close to the fabric. The thread end will disappear into the fold. Gently press the finished seam with your fingers or an iron to flatten it and blend it with the rest of the fabric.
Common Mistakes and How to Avoid Them
The most common mistake is catching too much fabric when you push the needle into the opposite fold. If you grab a large chunk of the main fabric instead of just the fold, the stitch will show on the outside. Push the needle in at a shallow angle so it enters the fold cleanly and stays inside the crease.
Another frequent problem is pulling the thread too tight too soon. This creates puckers and makes the seam look wavy instead of straight. Pull gently and only after several stitches have been made. If you see puckering, loosen the thread slightly by pushing the fabric back along the thread with your fingers.
Uneven stitch length makes the seam look sloppy even though it is hidden. Keep your stitches consistent—about one-quarter inch each—and space them evenly. If your stitches are too long, the opening will not close smoothly. If they are too short, the seam will take much longer to complete.
Frequently Asked Questions
Can I use a slip stitch on curved edges?
A slip stitch works on gentle curves, but sharp curves are difficult because the fold becomes hard to navigate. For curved seams, use shorter stitches and take your time. On very tight curves, a ladder stitch (which is similar but works differently) may be easier.
What thread weight should I use?
Use thread that matches your fabric weight. For lightweight cotton or linen, use a single strand of regular sewing thread. For heavier fabrics like denim or canvas, you can use two strands or a thicker thread. The thread should slide through the fabric without resistance but be strong enough not to break when you pull it snug.
How do I fix a slip stitch that shows thread on the outside?
If thread is visible, you caught too much fabric when you entered the opposite fold. Carefully remove the visible stitches by gently pulling the thread and using a seam ripper if needed. Re-stitch those stitches, entering the fold at a shallower angle so the needle stays inside the crease.
Do I need to backstitch at the end of a slip stitch?
No. The two small stitches in the same spot at the end create a find knot without backstitching. Backstitching would create visible bumps inside the fold. The double stitch in place is all you need to anchor the thread permanently.
Can I use a slip stitch to close seams on a sewing machine?
No. A slip stitch is a hand-sewing technique only. A sewing machine cannot replicate the motion of sliding through a fold and catching only a thread or two. For machine sewing, use a regular straight stitch or a ladder stitch done by hand if you want an invisible seam.