Sewing a cube means joining six square panels in the right order so the seams stay hidden and the shape holds its form

A sewn cube starts with six identical fabric squares cut to the same size. You sew them together in pairs, then join those pairs into a strip, then fold and close that strip into a box. The key is keeping your seam allowance consistent — usually a quarter inch — and sewing in an order that lets you turn the cube right-side-out through one opening before you close it completely. Most cubes are stuffed with fiberfill or left hollow, depending on what you want to use it for.

The whole project takes two to four hours depending on your sewing speed and whether you're hand-stitching or using a machine. You'll need thread that matches your fabric, a needle or sewing machine, scissors, a ruler, and pins. If you're making a toy or pillow, you'll also want fiberfill and a ladder stitch or whip stitch to close the final opening invisibly.

Key Takeaways

  • Cut six squares of fabric to identical size, then sew them into pairs, keeping a consistent quarter-inch seam allowance on all edges.
  • Join the three pairs into a strip by sewing them end-to-end, then fold that strip into a cube shape and sew the remaining edges closed.
  • Leave one seam partially open or one edge unsealed so you can turn the cube right-side-out and stuff it if needed.
  • Use a ladder stitch or whip stitch to close the final opening invisibly from the outside, so no raw seams show.

Cutting and preparing your fabric squares

Measure and cut six squares from your fabric. All six must be the same size — if they're not, the cube won't close evenly. A 4-inch square is a good starting size for a small cube; a 6-inch square makes a larger one. Add a quarter inch on all sides beyond your finished size to account for seam allowance. So if you want a finished 4-inch cube, cut each square 4.5 inches by 4.5 inches.

Mark the seam allowance lightly on the wrong side of each square using a ruler and pencil or fabric pen. This line shows you where to sew and keeps your stitches straight. Press all six squares with an iron to remove wrinkles — a flat, smooth surface is easier to sew accurately.

Sewing the first three pairs

Place two squares right sides together, so the fabric faces you see are touching and the wrong sides face outward. Pin along one edge, spacing pins about an inch apart. Sew along that edge using your marked seam allowance line as a guide. Backstitch at the start and end of the seam to lock the thread. Repeat this step with two more pairs of squares, so you have three pairs total.

Press each pair open after sewing so the seam lies flat. This makes the next step easier and gives you a cleaner finished cube. You now have three rectangular pieces, each made of two squares joined along one edge.

Joining the pairs into a strip

Lay the three pairs in a row. Sew them end-to-end by joining the short edge of one pair to the short edge of the next. Pin carefully so the corners line up, then sew with a quarter-inch seam allowance. You now have a long strip of six squares in a row, with five seams running across it.

Press all seams flat. This strip will become your cube when you fold and close it. At this stage, the strip looks like a paper chain made of fabric squares.

Folding the strip into a cube shape

Lay the strip flat with the seams facing up. Fold it so the first square and the last square face each other, bringing the two ends of the strip together. The four middle squares now form the four sides of the cube, and the two end squares will become the top and bottom.

Pin the two end squares together along their edges. Sew three of the four edges that connect them, using a quarter-inch seam allowance. Leave one edge completely unsealed — this is your opening for turning and stuffing. Backstitch at the corners to reinforce them.

At this point, your cube is still inside-out. The seams are on the outside and the right side of the fabric is hidden inside.

Turning the cube right-side-out and stuffing

Reach through the unsealed opening and gently pull the cube through it, turning it right-side-out as you go. Work slowly so you don't tear the seams. Once it's turned, use your fingers to push the corners out so they're sharp and square. Press the cube with an iron to set the shape, being careful around the opening.

If you're making a stuffed cube, fill it now with fiberfill or another stuffing material. Push the stuffing into the corners first, then fill the center. Don't overstuff — the cube should feel firm but not rock-hard. Leave a little room so the final seam closes smoothly.

Closing the opening with a ladder stitch

Fold the raw edges of the opening inward by a quarter inch and press them flat. Thread a needle with thread that matches your fabric. Knot the end of the thread and bring the needle up through the fold on one side of the opening, so the knot hides inside the fold.

Slide the needle along inside the fold for about a quarter inch, then bring it back out through the fold. Cross to the opposite side of the opening and repeat — slide the needle inside the fold, then bring it back out. This back-and-forth pattern is the ladder stitch. Pull the thread gently every few stitches so the opening closes invisibly. When you reach the end, knot the thread inside the fold and trim it.

Finishing touches and troubleshooting

Once the cube is closed, press it one more time with an iron to smooth any wrinkles and set the shape. If the corners look soft or rounded, use a point turner or the blunt end of a pencil to push them out from inside before you close the final opening.

If your seams are puckered or uneven, you may have pulled the fabric too tight while sewing. Loosen your tension slightly on your sewing machine, or sew more slowly by hand. If the cube won't close evenly, check that all six squares were cut to the same size — even a quarter-inch difference adds up across six pieces.

Frequently Asked Questions

Can I sew a cube by hand instead of using a machine?

Yes. Use a running stitch or backstitch and keep your stitches small and even — about an eighth of an inch. Hand-sewing takes longer but gives you more control over corners and curves. Use thread that matches your fabric and knot it securely at the start and end of each seam.

What fabric works best for a sewn cube?

Cotton, linen, and quilting cotton are easiest to work with because they hold a crease and don't fray as much. Avoid stretchy fabrics like knit or jersey unless you're experienced — they shift while you sew and make corners difficult. Felt doesn't fray at all, so it's good for beginners.

Do I have to stuff the cube?

No. You can leave it hollow to use as a decorative box, a storage container, or a toy. If you leave it hollow, close the final opening the same way — with a ladder stitch — so no seams show on the outside.

What size should I cut the squares?

That depends on what you're making. A 3-inch finished cube is good for a small toy or pincushion. A 4-inch or 5-inch cube works for storage or decoration. A 6-inch or larger cube is better for a floor cushion or a larger toy. Add a quarter inch to your finished size on all sides for seam allowance.

Why does one corner of my cube look bunched up?

This usually means the seams at that corner weren't sewn straight or the squares weren't cut to the same size. When you turn the cube right-side-out, gently work the corner from inside using a point turner or pencil eraser to push it out. If it still looks wrong, you may need to open that seam and resew it.