How to Knit a Bag: A Semi-Beginner Friendly Tutorial You Can Make in Any Size

Whether you’ve finished your first scarf and are itching to level up, or you’ve been knitting for a while and want a practical project to show off, a knitted bag is one of the most satisfying things you can make. It’s functional, it’s stylish, and once you understand the basic structure, you can adjust it to any size you want — from a tiny coin purse to a roomy market tote.

This tutorial walks you through everything: the materials you’ll need, how to think about sizing, the stitch pattern, construction steps, and finishing touches. You don’t need to be an expert. If you can cast on, knit, purl, and bind off, you have everything it takes to complete this project.

Let’s get into it.

What You’ll Need Before You Start

Before you cast on a single stitch, gather your supplies. Having everything on hand makes the process smoother and helps you avoid mid-project frustration.

Yarn. For a bag, you want something with structure — a yarn that holds its shape well and can handle the weight of whatever you’ll carry. Cotton, linen, jute, and wool blends are all excellent choices. Avoid anything too stretchy, like 100% acrylic yarn designed for garments, because your bag might end up saggy over time. A worsted-weight or bulky yarn works beautifully for beginners because it knits up quickly and is easy to see. For a standard tote-sized bag, you’ll need approximately 200–400 yards depending on your gauge and final dimensions.

Needles. Match your needle size to your yarn’s recommended gauge, but go down one size from what the label suggests. Because bags benefit from a tighter fabric that doesn’t stretch out or let small items fall through, a slightly firmer tension is your friend. If your yarn label says US 7 (4.5mm), try US 6 (4.0mm).

Stitch markers. These little rings are incredibly useful for marking corners, increases, or the beginning of a round if you’re working in the round.

Tapestry needle. You’ll use this to seam pieces together and weave in your ends.

Scissors.

Measuring tape.

Optional: a bag liner fabric and sewing needle/thread if you want a polished interior and extra durability.

Understanding Gauge and Why It Matters for Sizing

Here’s the part that makes this bag truly any size: gauge. Gauge is simply how many stitches and rows fit into a 4-inch square of your knitting. Every yarn and every knitter produces a slightly different gauge, and that’s perfectly okay — it’s actually the key to customizing your bag dimensions.

Before you start your actual bag, knit a small gauge swatch. Cast on about 20 stitches, work in your chosen stitch pattern for 4 inches, then bind off and measure. Don’t skip this step. It takes 15 minutes and saves you from ending up with a bag two sizes different from what you envisioned.

Let’s say your gauge is 18 stitches = 4 inches (or 4.5 stitches per inch). If you want a bag that’s 12 inches wide, you’d cast on approximately 54 stitches. If you want it 8 inches wide, you’d cast on about 36 stitches. It really is that straightforward.

Formula: (desired width in inches) × (stitches per inch) = cast-on number

Write down your gauge. You’ll reference it throughout the project.

Choosing Your Bag Size

Let’s talk about the most common bag sizes and what works best for each one.

Small clutch or pouch: roughly 6 inches wide by 5 inches tall. Perfect for a first bag project or as a gift.

Medium everyday bag: roughly 10–12 inches wide by 10–12 inches tall. This is the most versatile size — it fits a wallet, phone, keys, and a few extras without being bulky.

Large tote: roughly 14–16 inches wide by 14–16 inches tall. Ideal for the beach, the market, or carrying a book and a change of clothes.

Oversized market bag or beach bag: 18+ inches wide. These knit up fast with bulky yarn and chunky needles and feel incredibly satisfying to carry.

For this tutorial, I’ll walk through the construction of a medium bag — 10 inches wide by 10 inches tall — and explain exactly which numbers to change if you want a different size. Think of this as your template.

The Stitch Pattern: Seed Stitch

For a beginner-friendly bag with great texture and structure, seed stitch is the ideal choice. It lies flat (no curling edges like stockinette), it’s reversible (so the inside of your bag looks just as intentional as the outside), and it creates a dense, stable fabric. If you already love the look of stockinette or garter stitch, those work too — just note that stockinette has a tendency to curl at the edges, which can be managed with a border but adds a step.

Seed stitch pattern (worked flat over an even number of stitches):

Row 1: K1, P1 to end of row.
Row 2: P1, K1 to end of row.

Repeat these two rows. That’s it.

If you’re working over an odd number of stitches, every row is simply K1, P1 to the last stitch, K1. This is actually slightly easier to remember.

Construction Method: Knit Flat, Then Seam

There are two main ways to construct a knitted bag: working flat (back and forth in rows) and seaming the pieces together, or working in the round to create a seamless tube. Both produce beautiful results. For a semi-beginner project, working flat tends to be more approachable because you’re only ever looking at one side of the work at a time. We’ll go with that method here.

You’ll knit two identical rectangles — a front and a back — then seam them together along the bottom and two sides, leaving the top open. The strap is knitted separately and attached.

Step-by-Step: Knitting the Bag Body

Step 1: Cast on your stitches.

Using your gauge, calculate how many stitches you need for your desired width. For our 10-inch medium bag at 4.5 stitches per inch, that’s 45 stitches. Round to an odd number so the seed stitch pattern works out cleanly (as described above).

Use a long-tail cast on if you know it — it creates a firm, elastic edge that wears well on a bag. A regular knit cast on works fine too.

Step 2: Work the seed stitch pattern.

Begin working in seed stitch right away. There’s no need for a separate setup row. Work every row in seed stitch until your piece measures your desired height. For a 10-inch bag, that means knitting until the piece is 10 inches long.

Measure your work by laying it flat on a table and using a measuring tape. Don’t stretch it.

Step 3: Bind off.

When your piece reaches the right length, bind off loosely. A tight bind off at the top of a bag can make it awkward to open and close. If you tend to bind off tightly, try using a needle one size larger for the bind-off row only.

Step 4: Knit a second identical piece.

Repeat Steps 1–3 exactly to create the back panel of your bag. Both pieces should measure the same dimensions.

Sizing Adjustments at a Glance

Here’s how to scale the basic pattern up or down. Just plug your gauge into the formula.

For a small clutch (6 inches × 5 inches): cast on the number of stitches that gives you 6 inches of width, work until the piece is 5 inches long.

For a large tote (15 inches × 15 inches): cast on the number of stitches that gives you 15 inches of width, work until the piece is 15 inches long.

For a very wide, shallow bag like a bread-loaf style: make your cast-on wider than your height measurement — for instance, 14 inches wide by 8 inches tall.

For a tall, narrow bag: reverse it — cast on for 8 inches of width and work until you reach 14 inches in height.

The math is always the same. Gauge × desired dimension = your number.

Step-by-Step: Seaming the Bag

Once you have both panels knitted and your ends woven in (weave them in now, before seaming, because it’s much easier), it’s time to assemble the bag.

Seaming the bottom: Hold both panels with wrong sides facing each other and edges aligned. Thread your tapestry needle with a length of yarn (about 18 inches). Use a mattress stitch or whip stitch along the bottom edge to join the two panels. The mattress stitch creates a nearly invisible seam on the right side, which is lovely. The whip stitch is faster and slightly more visible but totally sturdy and fine.

Seaming the sides: With your bottom seam done, open the bag and seam up one side, then the other, working from the bottom up to the top opening. Again, mattress stitch gives the cleanest result. Make sure your seams are consistent in depth — picking up the same amount of fabric on each row — so the sides lie straight.

Once both sides are seamed, turn the bag right side out and give it a gentle press with a damp cloth or a steamer to help the seams lie flat and the fabric bloom a little.

Making the Strap

The strap is where you can really customize your bag. Here are three options, from simplest to slightly more involved.

Option 1: The I-cord strap. An I-cord is a narrow, rounded cord made by knitting a tiny tube. Cast on 3 or 4 stitches on double-pointed needles. Knit across. Without turning your work, slide the stitches back to the right end of the needle, bring the yarn around the back, and knit across again. Repeat until your cord is the desired length. This creates a surprisingly tidy, rope-like strap. For a shoulder bag, aim for about 24–30 inches of finished i-cord. For a crossbody, aim for 48–54 inches.

Option 2: The flat knitted strap. Cast on 8–12 stitches and work in seed stitch until your strap is the desired length. This creates a wide, flat strap that distributes weight comfortably across the shoulder. Bind off. This is the easiest method and the most beginner-friendly.

Option 3: Two handles. Instead of one long strap, make two short handles. Cast on 8–10 stitches and work in seed stitch for 10–12 inches. Bind off. Make two. These get attached to the front and back of the bag for a handheld tote style.

Attaching the strap: For a single shoulder strap, fold each end of the strap down about an inch and pin it to the inside of the bag at the top corners. Use your tapestry needle to stitch across several times, then stitch a small X through the strap for extra security. Do this on both sides. For two handles, attach each handle end to either side of one panel, then repeat on the back panel.

Optional: Adding a Bottom Gusset

If you want your bag to have depth and stand up on its own, you can add a simple gusset to the bottom. This is an optional step but it transforms the bag from flat to three-dimensional.

After you’ve seamed the bottom and sides of your bag, pinch the bottom corners of the bag so that the bottom seam and the side seam line up on top of each other, forming a triangle point. Stitch straight across the triangle point, perpendicular to both seams, about 1–2 inches from the tip. Do both corners. When you turn the bag right side out, the bottom will be flat and the bag will stand up on its own. The depth of the gusset is determined by how far from the tip you stitch: 1 inch of stitching = about 2 inches of gusset depth.

Optional: Lining Your Bag

Lining adds a polished, professional look and protects your knitting from wear. It’s easier than it sounds.

Cut two rectangles of lining fabric (cotton canvas, denim, and quilting cotton all work well) the same size as your knitted panels, plus half an inch on each side for seam allowance. Sew the lining panels together on three sides (bottom and both sides), leaving the top open. Fold the top edge down by half an inch and press it. Drop the lining into the bag wrong-side-out, align the top edges, and slip stitch the lining to the inside of the bag just below the top edge. Done.

Finishing Touches and Care

Weave in any remaining ends thoroughly. Give the bag a final block — wet blocking works beautifully for cotton and linen yarns; steam blocking is better for wool. To wet block, submerge the finished bag in cool water, gently squeeze out the water (don’t wring), roll it in a towel to absorb excess moisture, and lay it flat to dry, shaping it to your desired dimensions.

For washing going forward: check your yarn label. Most cotton bags can be machine-washed on a gentle cycle in a mesh laundry bag. Wool bags should be hand-washed in cool water with a gentle soap.

Troubleshooting Common Issues

My bag is stretching out of shape. This usually means the yarn is too stretchy or the fabric is too loosely knitted. Try going down a needle size, or switch to a more structured yarn like cotton or linen for your next version.

My seams look uneven. Seaming takes practice. Try to work consistently, picking up the same strand on each row. Using the mattress stitch takes more time but the results are much more even than whip stitch for beginners.

My seed stitch looks lumpy. This is almost always a tension issue — common and fixable. Make sure your tension stays consistent as you switch between knit and purl stitches. Some knitters purl more loosely than they knit; if this is you, try purling through the back loop to tighten up those stitches.

My bag is bigger/smaller than I wanted. This is a gauge issue. Check that your swatch matches what you measured before starting. If the finished bag is consistently larger than planned, you need to cast on fewer stitches (or use a smaller needle). If it’s smaller, cast on more (or use a larger needle).

Making It Your Own

One of the best things about this pattern is how much room there is for creativity. You can stripe the bag by switching yarn colors every few rows. You can add a button closure by working a small buttonhole (yarn over, k2tog) near the center of the top edge on one panel and sewing a button to the other. You can add fringe, tassels, or a woven ribbon accent. You can knit a small pocket in a contrasting color and seam it to the outside of the front panel before assembling the bag.

The basic structure — two rectangles, seamed on three sides, with a strap — is endlessly adaptable. Once you’ve made one, you’ll find yourself reaching for scraps of yarn and whipping up another in a different size without even thinking about it.

A Quick Reference Summary

Calculate your cast-on number using your gauge and your desired width. Work in seed stitch to your desired height. Knit two identical panels. Seam three sides. Add your chosen strap. Optional: add a gusset and/or a lining. Block and finish.

That’s the whole pattern. Knitting a bag from scratch is one of those projects that feels more impressive than it actually is to make — and that’s a genuinely wonderful thing. Give yourself a weekend, pour something warm to drink, and cast on. You might be surprised how quickly you get hooked on making these.