A hacky sack is a small, dense ball you can make with leftover yarn and basic knitting skills

A hacky sack is a stuffed knitted ball about the size of a walnut, filled with rice or sand to give it weight. You knit a flat square or rectangle, fold it in half, seam three sides closed, stuff it firmly, then seam the opening shut. The whole project takes two to four hours and uses only yarn you probably have at home. You do not need circular needles, a loom, or any special equipment — just straight needles, yarn, a tapestry needle, and something to fill it with.

The appeal is that hacky sacks are cheap to make, use up yarn scraps, and work as gifts or toys. A single hacky sack uses roughly 20 to 30 yards of yarn, so you can make several from a single skein. The finished ball is durable enough to kick around a yard or use in juggling practice, and the weight makes it feel substantial in your hand.

Key Takeaways

  • Knit a square roughly 4 inches by 4 inches using stockinette stitch, then fold it in half and seam three sides closed.
  • Stuff the ball firmly with uncooked rice, sand, or dried beans through the open side before closing the final seam.
  • Use yarn weight and needle size you are already comfortable with — worsted weight and size 6 to 8 needles work well for most people.
  • The entire project, from casting on to weaving in the last thread, takes between two and four hours for a beginner.

Cast on and knit a flat square

Cast on 16 stitches using the long-tail cast-on or whichever method you use regularly. Use needles one or two sizes smaller than the yarn label recommends — this tightens the fabric so the filling does not leak out. Knit every row in garter stitch (knit all stitches, every row) or stockinette stitch (knit one row, purl one row, repeat). Garter stitch is thicker and easier to count; stockinette is thinner and shows a smoother surface.

Work until your square measures roughly 4 inches by 4 inches. Count your rows as you go — you will need about 32 to 40 rows depending on your tension and yarn weight. The exact size does not matter much; anywhere from 3.5 to 4.5 inches on a side will work. Bind off all stitches loosely so the edge does not pucker when you seam.

Fold and seam three sides

Lay your square flat. Fold it in half with the right side facing out (or the side you prefer to show). Use a tapestry needle and a length of the same yarn to seam two adjacent sides closed using a whip stitch or mattress stitch — whichever you know. Work from the inside if you can, so the seams do not show on the outside. Leave one side completely open; this is where you will stuff the ball.

Pull your seaming yarn snug as you go, but do not pull so hard that you pucker the edges. A hacky sack does not need perfect seams — it will be kicked and squeezed, so function matters more than appearance. Once three sides are closed, you should have a pouch with one open edge.

Fill the ball with rice or sand

Uncooked rice is the most common filling because it is cheap, dense, and does not absorb moisture. Sand works too, as do dried beans or lentils. Avoid anything that will break down or go rancid — do not use flour or sugar. Measure out roughly 2 to 3 tablespoons of filling into a small bowl or funnel.

Hold the open edge of your knitted pouch and pour the filling in slowly. Shake the ball gently as you add filling so it settles evenly. Stop when the ball feels substantial but not rock-hard — you should be able to squeeze it slightly without it feeling like a stone. Too little filling and the ball will not kick properly; too much and it will be uncomfortable to hold or throw.

Close the final seam and weave in the ends

Once the ball is filled, fold the open edges inward and seam them closed using the same stitch you used for the other three sides. Pull the seaming yarn snug so no filling can escape. Tie off the yarn on the inside of the ball and weave the tail through a few stitches before cutting it short.

If you cast on with a separate length of yarn, weave that tail in as well. Trim any loose ends. Your hacky sack is now complete and ready to use. It will hold its shape through years of kicking and tossing, though the yarn will eventually pill or wear thin if you use it heavily outdoors.

Yarn weight and needle size matter less than you think

You can make a hacky sack from any yarn you have — fingering weight, worsted, bulky, or anything in between. Thinner yarn takes longer to knit but produces a denser, tighter ball. Thicker yarn knits faster but may have larger gaps that let filling escape. If you are worried about filling leaking through, use a needle one or two sizes smaller than the yarn label suggests, or line the inside with a small piece of cotton fabric before stuffing.

Beginners often worry they will make a mistake and ruin the project. A hacky sack is forgiving — dropped stitches, uneven tension, and crooked seams all disappear once the ball is stuffed and in motion. If you have never made one before, this is a good project to practice seaming and stuffing without the pressure of making something that has to look perfect.

Variations: color, shape, and filling options

Once you have made one hacky sack, you can experiment. Knit stripes by changing yarn color every few rows. Make a larger ball by casting on 20 stitches and working 50 rows instead of 32. Use two colors and knit a checkerboard pattern by carrying yarn up the sides. Make the ball heavier by using sand instead of rice, or lighter by using dried lentils.

Some people knit the ball in the round using circular needles or double-pointed needles, which eliminates seaming on two sides. That method is faster if you are comfortable with circular knitting, but the flat-square method works just as well and is easier for beginners. You can also knit a small rectangle, fold it into thirds, and seam it into a triangular pouch — the shape does not affect how the hacky sack performs.

Frequently Asked Questions

Can I use a different filling instead of rice?

Yes. Uncooked rice, sand, dried beans, and lentils all work well. Avoid anything that will absorb water, break down over time, or go bad — flour, sugar, and fresh beans are not suitable. The filling should be dense enough that the ball feels substantial when you kick it, so very light fillings like popcorn kernels will not work as well.

What if my seams are messy or uneven?

Messy seams do not matter in a hacky sack because the ball will be squeezed, kicked, and thrown. Once it is stuffed and in use, the seams are hidden inside or on the underside. Focus on making sure the seams are tight enough that filling does not leak out, not on making them look perfect.

How long does a knitted hacky sack last?

A well-made hacky sack lasts for years of casual use. The yarn will eventually pill, fade, or wear thin if you use it heavily outdoors or on rough surfaces. The filling can shift over time, but you can open a seam, add more filling, and close it again if needed.

Do I need special yarn or needles?

No. Any yarn and needles you already have will work. Worsted weight yarn and size 6 to 8 needles are comfortable for most people, but you can use thinner or thicker yarn if you prefer. The only rule is to use needles small enough that the finished fabric is tight enough to hold the filling.

Can I knit a hacky sack if I only know how to knit garter stitch?

Yes. Garter stitch (knitting every row) is actually easier for a hacky sack than stockinette because it is thicker and less likely to have holes. The finished ball will look slightly different — bumpy instead of smooth — but it will work just as well and may even be more durable.