Granny Square Bag Pattern: 3 Squares, 2 Seams, Any Size (Free)

If you’ve ever wanted a bag that looks complicated but is secretly one of the easiest things you’ll ever crochet, this granny square bag pattern is about to become your new favorite project. With just three granny squares, two seams, and a handful of supplies you probably already have in your stash, you can create a tote, shoulder bag, or purse in absolutely any size you want. No fussy construction, no confusing assembly, no sewing in a million ends. Just three squares, two seams, and a finished bag you’ll actually be proud to carry.

Whether you’re a brand-new crocheter who has just learned how to make a granny square or a seasoned maker looking for a quick weekend project, this pattern was designed with you in mind. Let’s walk through everything you need to know to make this bag from start to finish, including how to size it up or down for any occasion.

Why This Granny Square Bag Pattern Works So Well

The beauty of this design lies in its geometry. A granny square is, of course, a square. When you take three identically sized squares and seam two of them together along one edge each, you end up with a perfectly functional bag with a front panel, a back panel, and a bottom panel — all in one clean, flat assembly.

Think of it like folding a letter. You have your three sections: bottom, front, and back. The first seam connects the front panel to the bottom panel. The second seam connects the back panel to the bottom panel. Then you fold the assembly upward, join the side edges, and suddenly you have a three-dimensional bag with no complicated shaping required.

This method works because granny squares are already the perfect shape for a bag body. They’re sturdy, they have natural structure when worked in cotton or jute, and they can be made in virtually any size — from a coin purse to a large market tote — just by adjusting the number of rounds you crochet.

What You’ll Need

Before diving into the pattern itself, let’s cover the supplies. The beauty of this project is that the materials list is flexible, and you can substitute almost everything based on what you have available.

Yarn: For a bag that holds its shape and stands up to regular use, cotton yarn is ideal. Worsted weight or bulky weight cotton gives you a firm fabric that won’t stretch out of shape when loaded with your belongings. Jute or hemp twine also works beautifully for a natural, earthy aesthetic. If you’re making a decorative or lightweight bag for occasional use, any yarn weight can work, but keep structure in mind.

Hook: Match your hook to your yarn. For worsted weight cotton, a 5mm or 5.5mm hook is a great starting point. Going down a hook size from the yarn’s recommendation will give you a tighter, denser fabric that holds its shape better as a bag.

Notions: You’ll need a yarn needle for weaving in ends and seaming, scissors, and stitch markers if you like to keep track of rounds. For the strap, you can crochet one directly onto the bag, use pre-made bag handles, thread through a length of webbing, or add a chain strap — all of these options are covered below.

Optional: Magnetic bag closure, bag lining fabric, D-rings or swivel clips for an adjustable strap, and stitch markers.

How to Size Your Granny Squares for Any Bag Size

This is where the magic of the pattern really shines. Because the entire bag is built from three identically sized squares, you only need to decide on one measurement: how big you want your finished square to be.

Here’s a general guide to help you choose:

A 4-inch square made in fingering weight yarn gives you a tiny pouch or coin purse, perfect for tucking inside a larger bag or gifting as a small accessory.

A 6-inch square gives you a small bag similar in size to a clutch or small crossbody — good for a phone, cards, and keys.

An 8-inch square produces a medium-sized bag that works well as an everyday purse or a small project bag.

A 10-inch square gives you a generous tote-style bag suitable for beach trips, farmers markets, or grocery runs.

A 12-inch or larger square moves you into oversized tote territory — roomy enough for a laptop, a change of clothes, or a large crochet project.

Once you decide on your target size, crochet one test square and measure it. Adjust your hook size or add and subtract rounds as needed until you hit your target dimensions. Then crochet two more identical squares. That’s it. Your bag body is done.

The Classic Granny Square: A Quick Refresher

If you’re new to granny squares or want to use the traditional design for this bag, here’s a quick guide. The classic granny square is worked in joined rounds from the center out, with clusters of double crochet stitches separated by chain spaces.

Starting ring: Make a magic ring or chain 4 and join with a slip stitch to form a ring.

Round 1: Chain 3 (counts as first double crochet), work 2 double crochets into the ring, chain 2, [3 double crochets into the ring, chain 2] three more times. Join with a slip stitch to the top of the beginning chain-3. You now have four clusters with four corner spaces.

Round 2: Slip stitch into the first corner chain-2 space, chain 3, work 2 double crochets in the same space, chain 1, [3 double crochets, chain 2, 3 double crochets] in the next corner space (this creates the actual corner), chain 1, [3 double crochets in the side, chain 1, corner cluster, chain 1] repeat around. Join.

Subsequent rounds: Continue working in this manner, adding one cluster along each side per round and working the corner formula (3dc, ch2, 3dc) in each corner space. Each round makes the square one cluster larger on each side.

Keep going until your square is the size you need, then fasten off and weave in your ends. Block the squares if needed — this step makes a significant difference in how clean and even your finished bag looks.

Beyond the Classic: Other Square Options

One of the most fun parts of this pattern is that “granny square” is a broad term. You’re not limited to the traditional cluster-and-chain design. Any motif that results in a flat, even square can work for this bag.

Solid granny squares (worked in continuous rounds without chain spaces) create a dense, sturdy fabric that’s especially good for bags meant to carry heavier items.

Sunburst or flower center granny squares add a pop of color and texture to the front and back panels.

C2C (corner to corner) squares, worked diagonally in blocks, give a diagonal texture that looks striking on a bag.

You can even piece together multiple smaller squares to create one large patchwork panel — though at that point you’re technically using more than three squares total, the assembly method remains the same.

Assembling Your Bag: The 2-Seam Method

Now for the construction, which is where this pattern earns its “2 seams” name. Lay your three squares out flat in a row. The center square will be the bottom of your bag. The square on the left will be the front panel. The square on the right will be the back panel.

Seam 1: Join the left (front) square to the left edge of the center (bottom) square. You can seam with a slip stitch join, a whipstitch, a flat slip stitch seam, or a mattress stitch depending on the look you prefer. A slip stitch join worked from the outside gives a visible ridge that looks intentional and decorative. A mattress stitch worked from the inside gives a nearly invisible seam.

Seam 2: Join the right (back) square to the right edge of the center (bottom) square using the same method.

Now you have a long strip of three squares joined in a row. Fold the strip so the front and back panels stand upright with the bottom square flat between them. The front and back panels should face each other.

At this point, you’ll join the sides. Hold the front and back panels together with wrong sides facing each other (or right sides together if you prefer an inside-out seam), and slip stitch or seam along both open side edges from the bottom corner to the top corner. These side seams close up the bag and give it its three-dimensional shape.

When you open it up, you’ll have a perfectly formed bag with an open top, two flat panels, a flat bottom, and two tidy seamed sides.

Adding the Strap

The strap is where you can really customize this bag to suit your needs. Here are several options:

Crocheted chain strap: This is the simplest option. Using the same yarn as your bag, join your yarn to one side seam at the top, chain to your desired strap length, and attach to the opposite side seam. Work a row or two of single crochet back along the chain to give the strap body and prevent it from twisting. You can make it long for a crossbody bag or shorter for a shoulder bag.

Crocheted rectangular strap: Join your yarn to the side seam, then work rows of single crochet or half double crochet back and forth until the strap is the width and length you want. Fasten off and attach to the opposite side. This gives a flat, comfortable strap that sits nicely on the shoulder.

Wooden or bamboo handles: These pre-made bag handles are widely available at craft stores and online, and they look beautiful with a granny square bag. To attach them, fold the top edge of your front panel over the handle and seam it in place on the inside of the bag. Repeat for the back panel.

Webbing or leather strap: For a more utilitarian look, use a length of cotton webbing, nylon webbing, or leather strap threaded through D-rings attached to the side seams. This works especially well for larger tote bags.

Finishing Touches

Once your bag and strap are assembled, take a few minutes to add finishing details that will make your bag more functional and polished.

Top edge: Work a round of single crochet, reverse single crochet (crab stitch), or slip stitch around the top opening of the bag to neaten the edge and add structure. If you want a crisper opening, work two or three rounds.

Lining: For bags that will carry heavy or small items, a fabric lining is worth the extra effort. Cut a simple rectangle of fabric to match the interior of your bag, fold over the seam allowances, and hand stitch it in place along the top edge. This prevents items from poking through the crochet fabric and gives the bag a clean, professional interior.

Closure: A magnetic snap closure can be sewn to the lining at the top of the front and back panels. Alternatively, sew a button to the outside of the back panel and create a small crochet loop on the front panel to loop over it.

Stiffening: For very open lace granny squares, a light spray of starch or a fabric stiffener can help the bag hold its shape.

Pattern Tips for Success

A few notes that will save you time and frustration as you work through this project.

Always make your three squares at the same tension. If you switch yarn balls mid-project, the tension can shift. Winding all your yarn from the same skein and keeping your crochet rhythm consistent will help.

Block your squares before seaming. Even a quick wet block (soaking in water, squeezing out the excess, and pinning to dry flat) will even out any tension variations and make your squares easier to seam together neatly.

Join with a consistent method. Whichever seaming technique you choose, use it consistently on all four joining points (the two main seams plus the two side seams). This ensures your bag looks uniform from every angle.

Match your yarn colors intentionally. If you’re working in multiple colors, decide in advance whether you want each square to be different, whether you want a coordinated palette, or whether you want to use up scraps in a random, playful way. All three approaches look great — it just helps to have a plan.

Making It Your Own: Variations to Try

Because this pattern is essentially a framework rather than a rigid set of instructions, it lends itself beautifully to personalization. Here are a few variations worth exploring.

Color block bag: Use a different color for each of the three squares — a contrasting color for the front, a neutral for the bottom, and another accent for the back. Tie them together with a border round worked in one unifying color before seaming.

Tapestry or overlay crochet squares: For a more graphic, modern look, work your squares using tapestry crochet to create geometric patterns or even letters and initials.

Mixed texture bag: Work one square in a solid stitch (like moss stitch or waffle stitch) and the other two in the traditional granny square pattern for a textural contrast that still looks cohesive.

Asymmetrical size bag: While this pattern is designed around three equal squares, you can experiment with a slightly taller front and back panel paired with a shorter or narrower bottom square for a different silhouette.

A Note on Gauge and Yardage

Because this pattern is size-flexible, there’s no single gauge or yardage requirement. As a general rule, you can estimate that each square will use roughly the same amount of yarn, so calculate your yardage for one square and multiply by three, then add 15 to 20 percent extra for seaming and the strap.

For a medium-sized bag made in worsted weight cotton (approximately 8-inch squares), you’ll typically use somewhere in the range of 300 to 500 yards total depending on your chosen stitch pattern. For a large tote in bulky cotton, you might use 600 yards or more. Always buy a little extra — it’s much easier to have leftover yarn than to run out mid-project.

Why Granny Square Bags Are Having a Moment

It would be impossible to write about this pattern without acknowledging the larger cultural moment that granny square bags are enjoying right now. Once considered a craft your grandmother might make (hence the name), granny square designs have found their way onto high-fashion runways, into major retail stores, and all over social media feeds. Handmade crochet bags in particular have surged in popularity as people seek out unique, sustainable alternatives to mass-produced accessories.

Making your own granny square bag means you have a piece that is genuinely one of a kind. You choose the colors, the fiber, the size, and the style. No one else in the world has the exact bag you make, which is something no fast fashion brand can offer.

Final Thoughts

This granny square bag pattern is proof that great design doesn’t have to be complicated. Three squares, two seams, and a little imagination are all it takes to create a bag that’s functional, beautiful, and completely your own. The pattern scales to any size, works in any yarn, accommodates any style of granny square, and can be finished in a weekend or an afternoon depending on the scale you choose.

Whether you make it as a gift, a personal accessory, or the first in a long line of crocheted bags, you’ll find yourself coming back to this simple construction method again and again. Once you see how easily three squares fold into a perfectly shaped bag, it’s one of those techniques that changes the way you think about crochet construction forever.

Grab your hook, pull out your yarn stash, and get started. Your next favorite bag is just three squares away.