What a slip stitch is and when to use it

A slip stitch is a hand-sewing technique that closes a seam from the inside, leaving almost no visible thread on the outside. The needle travels inside the fold of fabric on one side, then slips through a few threads of the opposite fold, then back inside the first fold. Done correctly, the thread hides completely within the seam and the fabric lies flat.

Use a slip stitch to close openings in pillows, stuffed animals, and seams you've turned right-side-out. It's also the standard way to close the gap left when you turn a garment inside-out to sew it, then flip it back. Because the stitch is nearly invisible, it's the choice for any project where you don't want stitching to show on the finished side.

The slip stitch works best on seams that are already mostly closed—you're finishing the last 3 to 6 inches of an opening. It requires a needle that fits through your fabric without leaving large holes, thread that matches your fabric color, and a steady hand to keep stitches small and even.

Key Takeaways

  • Thread your needle with a single strand about 18 inches long, knotted at one end, and bring it up through the fold of fabric so the knot stays hidden inside the seam.
  • Insert the needle directly across from where it came out, into the opposite fold of fabric, and slide it along inside the fold for about a quarter inch before bringing it back out.
  • Return to the first fold, insert the needle directly across from where it exited, and repeat the back-and-forth motion, keeping stitches small and tension even.
  • The thread should run inside the fold of fabric on both sides, making it invisible from the outside when you pull the seam closed.
  • Finish by knotting the thread inside the seam, then weaving the needle through the fold for an inch before cutting the thread short.

Preparing your fabric and thread

Before you start stitching, make sure the opening is positioned so you can see and reach it easily. If you're closing a pillow or cushion, turn it right-side-out first so the seam allowance (the raw edges) is on the inside. The opening should have a clean fold of fabric on both sides—if the edges are raw or frayed, fold them inward about a quarter inch and press them flat with your fingers or an iron.

Use thread that matches your fabric color as closely as possible. A single strand works best for most fabrics; if your material is very thick or heavy, you can use a doubled strand, but this makes the stitch slightly more visible. Cut about 18 inches of thread, thread it through a needle with an eye small enough that the thread doesn't slide around, and tie a knot at one end. A small, tight knot works better than a large one because it's less likely to catch on fabric as you work.

Starting the stitch inside the seam

Insert your needle into the opening and push it up through the fold of fabric on one side, about a quarter inch away from the opening edge. The goal is to bring the needle out right at the fold line where the two pieces of fabric meet. Pull the thread until the knot catches inside the seam—it should be completely hidden, not visible from outside.

This first insertion is the most important step because it hides your starting knot. If the knot is visible on the outside of your project, the slip stitch won't look invisible. Take a moment to make sure the knot is truly inside the fold before you move forward. You should see thread coming out of the fold, but no knot.

The back-and-forth motion that creates the stitch

From where your thread exits the first fold, insert the needle directly across into the opposite fold of fabric. Don't go into the raw edge or the opening—go into the fold itself, the crease where the fabric bends. Once the needle is inside that fold, slide it along inside the fold for about a quarter inch, then bring the needle back out through the fold.

Now return to the first fold. Insert the needle directly across from where it just came out of the opposite fold, going into the fold itself. Slide the needle along inside this fold for another quarter inch, then bring it back out. You're creating a zigzag pattern: out of fold one, across into fold two, along fold two, out of fold two, back into fold one, along fold one, out of fold one, and repeat.

Keep your stitches small and even. Stitches that are too long will be visible and won't hold the seam closed securely. Aim for stitches about a quarter inch long on each side. Pull the thread gently as you work—not so tight that you pucker the fabric, but tight enough that the opening closes smoothly and the seam lies flat.

Closing the opening completely

Continue the back-and-forth motion until you reach the end of the opening. Your last stitch should come out of the fold on whichever side you're on, right at the point where the opening ends and the original seam begins. At this point, the opening should be completely closed and the fabric should lie flat with no gap.

If you notice the opening isn't closing evenly or one side is bunching, stop and adjust. You can gently pull the thread to tighten the seam, or you can go back a few stitches and re-do them with slightly different tension. It's better to fix it now than to finish and discover the seam doesn't look right.

Finishing and hiding the thread end

Once the opening is fully closed, bring the needle out through the fold on one side. Tie a small knot right at the fold, as close to the fabric as possible. You can do this by looping the thread around the needle once and pulling it tight, or by making a small loop and pulling the thread through it—either method works.

After you've tied the knot, insert the needle back into the fold and slide it along inside the fold for about an inch, the same way you did while stitching. This hides the knot inside the seam. Bring the needle out through the fold, pull the thread taut, and trim it short with scissors. The thread end will disappear back into the fold when you release it.

Common mistakes and how to avoid them

The most common error is stitching too close to the opening edge instead of inside the fold. If you stitch the raw edges together instead of the folds, the seam will be weak and the thread will be visible. Always make sure your needle is going into the fold—the crease of fabric—not the raw edge of the opening.

Another frequent problem is pulling the thread too tight, which puckers the fabric and makes the seam look bunched. Pull just enough to close the opening; the fabric should lie smooth and flat. If you've already pulled too tight, you can loosen it slightly by gently pushing the fabric along the seam with your fingers.

Stitches that are too long will show on the outside, especially if your thread doesn't match perfectly or if the fabric is light-colored. Keep stitches to about a quarter inch. If you're working with delicate or thin fabric, even smaller stitches—about an eighth inch—will give you a neater result.

Frequently Asked Questions

Can I use a slip stitch on seams that are already sewn by machine?

Yes. If you've sewn a seam by machine and left an opening to turn the fabric right-side-out, you can close that opening with a slip stitch. The machine-sewn seam on either side of the opening will hold the fabric in place while you stitch the gap closed by hand.

What if my thread keeps breaking or tangling?

Thread that's too long tangles easily—cut it to about 18 inches. If it keeps breaking, you may be pulling too hard; use lighter tension. Also check that your needle isn't bent or damaged, and make sure the thread isn't catching on rough spots in the fabric or the needle's eye.

How do I fix a slip stitch if I made a mistake?

If you notice a mistake right away, carefully cut the thread and pull it out. You can re-thread the needle and redo those stitches. If the mistake is further back, it's usually easier to leave it and continue forward—a single misplaced stitch won't weaken the seam much.

Is a slip stitch strong enough for items that get a lot of use?

A slip stitch is strong when done correctly, but it's not as durable as a machine-sewn seam. For pillows and stuffed items that don't get heavy stress, it's fine. For items that will be washed frequently or handled roughly, reinforce the slip stitch by sewing a second row of stitches parallel to the first, about a quarter inch away.

Can I use a slip stitch on stretchy fabrics like knit or jersey?

Slip stitches work on knits, but the seam may stretch out over time because hand stitching is less stable than machine stitching. If you're closing a knit garment, use a doubled thread for extra strength, keep stitches small, and consider using a backstitch instead for seams that will get a lot of movement.