A straightforward bag takes just yarn, needles, and a few hours

A knitting bag is one of the easiest projects to finish once you know how to cast on, knit, and bind off. The basic version is a flat rectangle that you fold in half and seam up the sides, then thread a cord through the top to close it. You do not need to increase, decrease, or change colors—just knit the same stitch in the same way for every row until the piece is big enough, then stop. Most people finish one in an afternoon or two.

This guide walks you through the whole process: choosing yarn weight and needle size, casting on the right number of stitches, knitting to the right dimensions, and finishing the bag so it actually holds things without unraveling.

Key Takeaways

  • A basic knitting bag uses worsted weight yarn (medium thickness) and needles one or two sizes larger than the yarn label recommends, which creates a loose, flexible fabric.
  • Cast on 30 to 40 stitches and knit in garter stitch (knit every row) until the piece measures 10 to 12 inches tall, then bind off.
  • Fold the rectangle in half with the knit side facing out, seam the two side edges closed with yarn and a tapestry needle, and weave in loose ends.
  • Thread a 24-inch cord (yarn, ribbon, or paracord) through stitches near the top edge using a tapestry needle, then tie the ends together to create a drawstring.
  • The finished bag will stretch slightly as you use it, so do not worry if it feels loose when you first bind off.

Choosing yarn and needles for a bag that holds its shape

Worsted weight yarn (also called medium or #4 weight) is the best choice for a beginner bag. It is thick enough that you finish quickly, loose enough that you can see your stitches clearly, and sturdy enough that the finished bag will not sag. Acrylic yarn works fine and costs less than wool; wool holds its shape better over time but is more expensive and can feel itchy if you have sensitive skin.

Look at the yarn label for the recommended needle size—usually US 7 to US 9 for worsted weight. Use needles one or two sizes larger than the label says. This creates a looser fabric that is flexible and drapes well, which is what you want in a bag. If you use needles that are too small, the bag will be stiff and hard to close.

You will need roughly 200 to 300 yards of yarn for a medium-sized bag. One or two balls of worsted weight yarn is usually enough. Buy a ball, check the yardage on the label, and if it is less than 200 yards, pick up a second ball.

Casting on and setting up your rectangle

Cast on 32 stitches using the long-tail cast-on or any method you are comfortable with. This number creates a bag that is roughly 8 inches wide when finished—wide enough to hold yarn, notions, or small projects, but not so wide that it is floppy.

If you want a narrower bag (for a phone or small items), cast on 24 stitches instead. If you want a wider bag (for a full-sized project), cast on 40 stitches. The width of the finished bag will be roughly three-quarters of the number of stitches you cast on, measured in inches, because knit stitches are wider than they are tall.

Once you have cast on, check that all your stitches are sitting on the needle and facing the same direction. Twisted stitches will create a twisted bag. Slide them to the middle of the needle so they do not fall off, and you are ready to knit.

Knitting the body in garter stitch

Garter stitch means knitting every stitch in every row. Do not purl. Just knit across, turn the needle, and knit across again. This is the easiest stitch and creates a bumpy, textured fabric that looks the same on both sides—perfect for a bag because there is no "wrong" side to hide.

Knit until your piece measures 10 to 12 inches from the cast-on edge. Measure along the side edge, not across the stitches, because the stitches themselves are not a reliable measure. A typical row of garter stitch is about one-quarter inch tall, so you will need roughly 40 to 50 rows. Count your rows by looking at the bumps on the side edge—each bump is one row.

Do not worry about making the edges perfectly straight. Garter stitch naturally creates a wavy edge, and that is fine. The seams will tighten it up later.

Binding off and finishing the edges

Once you reach the right height, bind off all your stitches. Use the standard bind-off: knit two stitches, pass the first stitch over the second, knit one more stitch, pass the stitch before it over the new stitch, and repeat until you have one stitch left. Cut the yarn, pull the tail through the last stitch, and pull tight.

You now have a flat rectangle. Weave in the loose ends from the cast-on and bind-off using a tapestry needle (a large, blunt needle with an eye big enough for yarn). Thread the tail through the needle, run it through the bumps along the edge for about an inch, then trim the excess. This keeps the ends from unraveling.

Seaming the sides to create the bag shape

Lay the rectangle flat with the knit side facing up. Fold it in half lengthwise so the two short edges meet. The fold is the bottom of your bag.

Thread a tapestry needle with a length of yarn about 3 feet long—the same color as the bag, or a color that matches closely. Starting at the bottom corner, use the mattress stitch to seam the two side edges together. The mattress stitch is invisible from the outside: insert the needle under the first stitch on one edge, then under the first stitch on the other edge, then back under the second stitch on the first edge, and so on. Pull the yarn snug every few stitches so the seam closes neatly.

Seam all the way up both sides until you reach the top. Weave in the tail. You now have a bag with a closed bottom and two open sides at the top.

Adding a drawstring to close the bag

Cut a length of yarn, ribbon, or paracord about 24 inches long. This will be your drawstring. If you use yarn, choose something sturdy—worsted weight or heavier works better than thin yarn, which can break under tension.

Thread the drawstring onto a tapestry needle. Starting at one side seam, insert the needle under the stitch just below the bind-off edge, pull the needle through, and move one stitch to the right. Insert the needle under the next stitch, pull through, and repeat all the way around the top of the bag. When you reach the starting point, thread the needle under the first stitch again so the drawstring forms a loop.

Tie the two ends of the drawstring together in a square knot. Pull the knot tight so it does not slip through the stitches. When you pull the drawstring, the top of the bag will cinch closed.

Common mistakes and how to avoid them

Casting on too few stitches creates a bag that is too narrow to be useful. If you are unsure, cast on 32 and measure as you go. You can always make a second bag if the first one is too small.

Using needles that are too small makes the fabric tight and stiff. If your bag feels like cardboard, you used the wrong needle size. Rip it out and start over with larger needles—it is faster than fighting a stiff bag for months.

Forgetting to weave in the ends before seaming means loose tails will stick out of the finished bag. Weave them in as you go, not at the end.

Pulling the seam too tight makes the bag pucker and distorts the shape. Seam snugly, but not so tight that you can see the individual stitches bunching. The seam should be smooth and invisible from the outside.

Frequently Asked Questions

Can I use a different stitch instead of garter stitch?

Yes. Stockinette stitch (knit one row, purl one row) works but curls at the edges, so you would need to add a border. Seed stitch (alternating knit and purl stitches) looks nice but takes longer. Garter stitch is the fastest and does not curl, so it is the best choice for a first bag.

What if my bag is too loose and stretches out of shape?

Garter stitch bags stretch slightly when you fill them, and that is normal. If it stretches too much, you used needles that were too large. Next time, use needles one size smaller than you did this time. You can also wash and block the finished bag to reshape it—lay it flat, wet it, and let it dry in the shape you want.

Can I make the bag bigger or smaller?

Yes. Cast on fewer stitches (20 to 24) for a small bag, or more stitches (40 to 48) for a large one. Knit for 8 to 10 inches for a shallow bag, or 12 to 14 inches for a deep one. The finished size will be roughly three-quarters of the number of stitches, by the number of rows divided by four.

Do I have to use a drawstring, or can I close it a different way?

A drawstring is the simplest closure. You can also add a button and loop, or fold the top edge down and seam it closed, but those take more steps. A drawstring is fast and adjustable, so it works best for a first bag.

What should I put in my finished bag?

A knitting bag is perfect for holding yarn, needles, stitch markers, and a project in progress. It is also useful for notions, small tools, or anything you want to keep together. The loose fabric stretches to fit what you put inside, so do not worry about overstuffing it.