The two stitches that hold fabric together

A hand-sewn seam uses one of two stitches: the running stitch or the backstitch. The running stitch is faster and works for seams that won't take much stress — hems, light repairs, decorative work. The backstitch is slower but much stronger and is the one to use for seams that need to hold: garment seams, bag construction, anything that will be worn or carried. Both use the same basic motion: thread through needle, push the needle through both layers of fabric, pull the thread snug, and repeat.

Before you start, you need a needle, thread, two pieces of fabric, and scissors. Pin the two fabric pieces together with the sides you want to show facing outward, or with the sides you want hidden facing each other — it depends on the project. Cut a length of thread about as long as your arm, thread it through the needle, and tie a knot at the end.

Key Takeaways

  • The running stitch is quick but weak; use it for hems and repairs that won't take stress.
  • The backstitch is slower but strong enough for garment seams and anything that needs to hold.
  • Both stitches start with the needle pushed through from the back of the fabric so the knot stays hidden.
  • Keep your stitches small and even — stitches smaller than a grain of rice are stronger and look better.
  • Backstitch by pushing the needle backward through the fabric, then forward two stitch-lengths ahead, then backward again into the end of the last stitch.

How to sew a running stitch

Push the needle up through both layers of fabric from underneath, about a quarter-inch from where you want the seam to start. Pull the thread until the knot catches on the back of the fabric. This hides the knot inside the seam.

Push the needle down through both layers about a quarter-inch forward along the line where you want the seam. Push it back up another quarter-inch forward. Keep doing this — down, up, down, up — in a straight line. The stitches on top and bottom should be the same size. Smaller stitches are stronger, so aim for stitches no bigger than a grain of rice.

When you reach the end of the seam, push the needle to the back of the fabric and tie off the thread by making a small loop, pushing the needle through it, and pulling tight. Trim the thread close to the knot.

How to sew a backstitch

Push the needle up through both layers from underneath, about a quarter-inch from where you want the seam to start. Pull the thread until the knot catches on the back.

Push the needle down through both layers, then when ready back up again about a quarter-inch forward. Now push the needle backward through the fabric, going back into the hole where the last stitch ended. This creates an overlap — the thread on the back forms a solid line even though you are moving forward on top. Push the needle forward again a quarter-inch ahead, then backward into the end of that stitch. Repeat: forward a quarter-inch, backward into the last hole.

The backstitch creates a strong seam because each stitch locks into the one before it. On the front of the fabric, you see a solid line. On the back, you see overlapping stitches. This is what makes it strong enough for seams that will be pulled or stressed.

Keeping stitches even and straight

The easiest way to sew a straight seam is to mark a line first. Use a pencil, a fabric pen, or a ruler and tailor's chalk to draw a light line on the fabric where you want the seam to go. Then sew along that line. If you do not mark a line, use the edge of the fabric as your guide — sew a quarter-inch in from the edge, or whatever distance you chose at the start.

Stitches that are uneven in size are weaker than stitches that are all the same. Aim for each stitch to be the same length as the one before it. If you find yourself making stitches that are too big, slow down. It is better to sew slowly and keep the stitches small than to rush and have loose, uneven work.

If a stitch goes in the wrong place, pull the thread backward to undo it, then start again from where you went off the line. You do not need to undo the whole seam.

Choosing thread weight and fabric thickness

Use thread that matches the weight of your fabric. Lightweight fabric like cotton voile or linen takes regular sewing thread. Medium-weight fabric like cotton quilting fabric or linen takes the same thread. Heavy fabric like denim, canvas, or upholstery fabric is easier to sew with buttonhole thread or upholstery thread, which is thicker and stronger. If you use thin thread on heavy fabric, the thread may break under stress.

Thicker fabric also needs a larger needle. A size 7 or 8 needle works for most cotton and linen. A size 9 or 10 works for heavier fabric. If the needle is too small, it will bend or break. If it is too large, it will leave visible holes in the fabric.

When to use each stitch in real projects

Use the running stitch for hems on lightweight garments, for seams on decorative projects where strength is not critical, and for repairs that are temporary or will not take much wear. A running stitch on a pillowcase hem or a straightforward repair to a cotton shirt is fine because the seam is not under constant stress.

Use the backstitch for any seam that will be worn, washed, or stressed: the side seams of a garment, the seams on a bag you will carry, the seams on anything that needs to last. A backstitch on a tote bag or a dress seam will hold through years of use. If you are not sure which to use, backstitch — it is slower but you will not regret the strength.

Fixing mistakes and reinforcing weak spots

If you notice a seam is coming apart or a stitch has broken, you do not need to resew the whole seam. Tie off the thread at the end of the good stitches, then start a new thread a quarter-inch before the break and sew forward past the break by a quarter-inch. This overlap reinforces the weak spot.

If a seam is pulling apart because the stitches are too far apart or the thread is too thin, you can sew a second line of stitches right next to the first one. This is called a double seam and is much stronger than a single line. Sew the second line a quarter-inch away from the first, using the same stitch type.

Frequently Asked Questions

How do I know if my stitches are tight enough?

Pull gently on the seam. The thread should not slide through the fabric, and the fabric should not pucker or wrinkle. If the thread is loose, pull it snug as you sew the next few stitches. If the fabric puckers, you are pulling too hard — ease up slightly.

What do I do if the thread keeps knotting or tangling?

Cut a shorter length of thread — about 18 inches instead of arm's length. Longer thread tangles more easily. Also check that the thread is going through the needle the same direction it came off the spool. If it is twisted, unthread it and rethread it correctly.

Can I use a backstitch on stretchy fabric like knit or jersey?

A backstitch on stretchy fabric will eventually break because the thread does not stretch with the fabric. For knits, use a running stitch with a slight zigzag motion, or hand-sew with elastic thread. For most projects, machine sewing is better for stretchy fabric.

How close to the edge should the seam be?

A quarter-inch from the edge is standard for most sewing. For lightweight fabric, you can go closer — an eighth-inch is fine. For heavy fabric or seams that will take stress, stay a quarter-inch or more from the edge so the thread does not pull through the fabric.

What if I run out of thread in the middle of a seam?

Tie off the thread on the back of the fabric, then thread a new needle and start again a quarter-inch before where you stopped. Sew forward, overlapping the old stitches slightly. This join will be strong because the stitches overlap.