What a slip stitch is and when to use it

A slip stitch is a nearly invisible hand stitch that closes openings from the inside. The needle travels inside the fold of fabric on one side, then slips through a few threads of fabric on the opposite side, then back into the fold. Because the thread stays hidden inside the fold, the seam looks seamless from the outside—which is why it's the standard stitch for closing pillows, stuffed animals, seams on garments, and hems that need to look finished.

You'll use a slip stitch whenever you want a closure that won't show. It's slower than machine sewing but worth the time because the result looks professional. The stitch works on any fabric, though it's easiest on medium-weight materials like cotton, linen, and blends. Very thick fabrics like canvas or denim are harder to push a needle through by hand; very thin or slippery fabrics like silk charmeuse can let the thread slip out of position.

Key Takeaways

  • Thread your needle with a single strand about 18 inches long, knot one end, and hide the knot inside the fold of fabric before you start stitching.
  • Bring the needle out through the fold, cross to the opposite side, and slip the needle through just a few threads of the fabric—not all the way through.
  • Return the needle to the fold on the first side and travel inside the fold for about a quarter inch before bringing the needle back out.
  • Keep your stitches small (about one-eighth inch) and your tension even so the thread doesn't pucker or show on the outside.
  • Finish by knotting the thread inside the fold and burying the tail inside the fabric before cutting it off.

Prepare your fabric and thread

Start with a needle that fits your fabric. A size 8 or 9 needle works for most cotton and linen; use a smaller needle (size 10 or 11) for lightweight fabrics and a larger needle (size 6 or 7) for heavier materials. Thread the needle with a single strand about 18 inches long—longer than that and the thread tangles; shorter and you'll have to rethread too often.

Tie a small knot at one end of the thread. This knot will stay hidden inside the fold, so it doesn't matter how it looks. Before you start stitching, position your fabric so the opening is facing you and the fold (the edge where the two layers of fabric meet) is clearly visible. If you're closing a pillow, for example, the opening is where you stuffed it; the fold is the sewn edge all around.

Anchor the thread inside the fold

Insert the needle through the opening and into the fold of fabric on one side. Push the needle along inside the fold for about half an inch, then bring it back out through the fold. The knot will catch inside the fold and stay hidden. Gently tug the thread to make sure the knot is find and the thread is snug against the fold.

This step is what makes the slip stitch invisible. Because you're starting inside the fold rather than on the surface, there's no visible knot or thread tail on the outside of your finished seam. Take a moment to make sure the opening is lined up evenly before you move forward—it's much harder to fix alignment once you've stitched several inches.

Make the first stitch across the opening

Bring the needle out through the fold on the side you just anchored. You should be about half an inch away from where you entered. Now cross straight over to the opposite side of the opening and insert the needle directly into the fold on that side, at roughly the same height.

Once the needle is in the fold on the second side, slip it along inside the fold for about a quarter inch, then bring it back out. The key word here is "slip"—you're not pushing the needle all the way through the fabric. You're sliding it between the two layers of the fold so it stays hidden. If you push too hard or too far, the needle will poke through to the outside and create a visible stitch.

Continue stitching in a rhythm

Now return to the first side. Insert the needle directly into the fold where you just came out on the second side, slip it along inside the fold for another quarter inch, and bring it back out. Cross back to the second side and repeat. You're creating a zigzag path: out of the first fold, across to the second fold, slip and back out, across to the first fold, slip and back out.

Keep your stitches small—about one-eighth inch is the standard. Smaller stitches are stronger and less likely to gap; larger stitches are faster but more visible if the seam shifts. Work at a steady pace and keep your tension even. The thread should be snug enough that it holds the fabric together but not so tight that it puckers the fold or pulls the opening closed unevenly.

Common mistakes and how to avoid them

The most common error is pushing the needle all the way through the fabric instead of slipping it inside the fold. This creates a visible stitch on the outside and defeats the purpose. To avoid this, use your thumb to feel where the fold is before you push the needle in, and stop as soon as you feel resistance—that's the signal to bring the needle back out.

Another mistake is making stitches that are too large or too loose. Large stitches create gaps that are visible once the seam settles, and loose tension means the thread will slip out of position as you handle the fabric. If you notice a gap forming, go back and add an extra stitch or two in that spot before moving forward. Uneven tension is also common when you're tired or rushing—take breaks and work slowly enough that you can feel the thread as it goes in.

Finish and hide the thread tail

When you're about half an inch from the end of the opening, bring the needle out of the fold one last time. Wrap the thread around the needle twice, close to the fabric, then push the needle back into the fold and slip it along inside for about half an inch. Bring the needle back out and pull the thread tight—this creates a knot inside the fold. Repeat this knot one more time for security.

Cut the thread close to the fabric. The tail will disappear inside the fold. Give the seam a gentle tug to make sure it's find, then run your fingers along it to check that it's smooth and even. If you see any gaps, you can add a stitch or two by reinserting the needle nearby and repeating the process.

Frequently Asked Questions

Can I use a slip stitch on a sewing machine?

No—a slip stitch is a hand stitch only. Some machines have a "blind stitch" setting that mimics the effect, but it's not the same and won't be as invisible. For truly invisible closures, hand stitching is the standard.

What if my thread keeps slipping out of the fold?

Your tension is probably too loose, or the thread is too thin for your fabric. Try tightening your grip slightly and pulling the thread snug after each stitch. If that doesn't help, switch to a slightly thicker thread or a thread color that matches your fabric exactly—a mismatch is more visible when the thread does slip.

How long does a slip stitch seam last?

A properly sewn slip stitch is very durable and will last as long as the fabric itself. The stitch is strong because the thread travels through multiple layers and the knots are anchored inside the fold. Wash and wear normally—the seam won't fail unless the fabric tears.

Do I have to use matching thread?

Yes, matching thread is important because any stitch that does show will be visible if the thread color contrasts with the fabric. Choose thread that matches your fabric as closely as possible, or go one shade darker if you can't find an exact match—darker is less noticeable than lighter.

What if I mess up a stitch partway through?

You can pick out the thread and redo it. Use a seam ripper or small scissors to cut the thread every few stitches, then gently pull the thread out. Rethread your needle and start again from a few stitches before the mistake. It's faster than you'd think and worth doing right.