What You'll Make and What You Need

A basic backpack is a rectangle of fabric folded in half, sewn on three sides, and fitted with two shoulder straps. You can finish one in an afternoon if you have a sewing machine. This guide walks you through making a backpack roughly 14 inches wide by 16 inches tall—large enough for books or groceries, small enough to handle as a first project.

Gather these materials before you start: two pieces of sturdy fabric (canvas, denim, or heavy cotton work well), each 15 inches wide by 17 inches tall; two strips of webbing or heavy fabric for straps, each 2 inches wide by 30 inches long; thread that matches your fabric; a sewing machine; scissors; pins; and a measuring tape. You will also need a needle for hand-stitching the final seams if your machine struggles with thick layers.

If you do not have webbing, you can make straps by folding and sewing fabric strips, but webbing is faster and holds its shape better under weight. Most fabric stores sell it in the notions section for a few dollars per yard.

Key Takeaways

  • Cut two identical rectangles of fabric and prepare your straps before you touch the sewing machine.
  • Sew the two fabric pieces together on three sides with a half-inch seam allowance, leaving the top open.
  • Attach the straps to the inside of the backpack at the top corners before closing the final seam.
  • Reinforce the strap attachment by sewing a small square or X shape at each corner to distribute weight.
  • A basic backpack takes two to four hours from cutting to finished product, depending on your sewing speed.

Cutting and Preparing Your Pieces

Lay your first piece of fabric on a flat surface and measure out a rectangle 15 inches wide by 17 inches tall using a measuring tape and ruler. Mark the corners lightly with a pencil or fabric pen. Cut along the lines with sharp fabric scissors—dull scissors will fray the edges and make sewing harder. Repeat with your second piece of fabric so you have two identical rectangles.

Next, prepare your straps. If you are using webbing, cut two pieces, each 30 inches long. If you are making straps from fabric, cut two strips 4 inches wide by 30 inches long, fold each strip in half lengthwise with the right sides facing inward, sew along the long edge with a quarter-inch seam allowance, turn the tube right-side out, and press flat with an iron. This takes extra time but gives you custom straps that match your fabric.

Lay both fabric rectangles on top of each other with the right sides (the pretty sides) facing each other. Pin around all four edges to hold them in place. This is called the "wrong side out" position—you will sew with the good sides hidden and flip the whole thing right-side out at the end.

Sewing the Main Body of the Backpack

Thread your sewing machine with thread that matches your fabric. Set the stitch length to a medium setting (around 2.5 millimeters) and the tension to normal. Start at one of the bottom corners and sew along the bottom edge with a half-inch seam allowance—that means your needle should run half an inch away from the edge of the fabric. Sew slowly and keep the edge of the fabric aligned with the half-inch mark on your presser foot.

When you reach the next corner, stop with the needle down, lift the presser foot, rotate the fabric 90 degrees, lower the presser foot, and continue sewing up the side. Repeat at each corner. Sew all the way around three sides—bottom, left, and right—but stop at the top and leave it open. This opening is where you will attach the straps and where you will turn the backpack right-side out later.

Backstitch at the beginning and end of each seam by pressing the reverse button for three or four stitches. This locks the thread so it will not unravel. If your fabric is very thick or your machine struggles, sew slowly and do not force the fabric through—let the machine feed it at its own pace.

Attaching the Straps Before Closing the Top

This step is the key to a backpack that will not fall apart. Before you close the top seam, you must sew the straps to the inside of the backpack at the top corners. Lay the backpack flat with the wrong side still facing out (the two fabric pieces still sewn together but not yet flipped). Take one strap and fold it in half to find the midpoint. Pin the midpoint to the inside of the backpack at one top corner, about one inch down from the top edge. The two ends of the strap should hang down into the backpack.

Sew the strap in place with a small square: start at the top of the strap, sew down one inch, across one inch, back up one inch, and across again to close the square. This distributes the weight across a wider area and prevents the strap from tearing free. Repeat with the second strap at the other top corner. Make sure both straps are pinned at the same distance from the top and the same distance from the corner, or your backpack will hang crooked.

After both straps are sewn, flip the backpack right-side out through the top opening. Push the corners out gently with your fingers so they are sharp and square. Press the backpack flat with an iron, paying special attention to the top edge where the opening is.

Closing the Top Seam and Reinforcing the Straps

Fold the raw edges of the top opening inward by half an inch on both pieces of fabric and press them flat. Pin the opening closed. Sew along the top edge with a half-inch seam allowance, backstitching at the start and end. This seals the backpack and hides the raw edges inside.

Now reinforce the strap attachment from the outside. At each top corner where a strap is sewn, sew an X shape or a small square over the existing stitches. This second layer of stitching prevents the strap from pulling loose when the backpack is full and heavy. Use a needle and thread by hand if your machine cannot reach the corner easily, or use your machine with the presser foot lifted slightly to navigate the thick layers.

Try on the backpack and adjust the strap length if needed. If the straps are too long, you can fold them and sew them shorter. If they are too short, you can add fabric or webbing to extend them. Most people prefer straps that sit comfortably on the shoulders when the backpack is on their back.

Common Mistakes and How to Avoid Them

The most common error is sewing the straps to the outside of the backpack instead of the inside. If you do this, the stitches will show and the straps will be weaker. Always attach straps before you flip the backpack right-side out. The second mistake is leaving the seam allowance too small—less than half an inch—which makes the seams weak and prone to splitting. A half-inch seam allowance is standard for bags because it spreads the stress across a wider area of fabric.

A third mistake is not reinforcing the strap attachment. A single row of stitches will hold a light backpack, but anything heavier will eventually tear the straps free. The small square or X you sew over the strap attachment is not decoration—it is structural. Do not skip it.

Finally, do not use fabric that is too thin. Lightweight cotton or linen will work for a small bag, but for a backpack that will carry weight, use canvas, denim, or heavy cotton twill. Thin fabric will stretch and sag, and the straps will pull the fabric out of shape. If you are unsure whether your fabric is heavy enough, hold it up to the light—you should barely be able to see through it.

Customizing Your Backpack

Once you have made one basic backpack, you can add features. A pocket on the front or back is straightforward: cut a rectangle of fabric, fold the top edge down and sew it, then pin the pocket to the outside of the backpack and sew around three sides. A zippered opening at the top is more advanced but possible if you have sewn a zipper before—you will need to insert it before you close the top seam.

You can also add a bottom panel to make the backpack more structured. Instead of sewing two rectangles together, cut a separate piece for the bottom, sew it to the sides and back, and then sew the front piece on last. This creates a box shape that holds its form better. Experiment with different fabrics, colors, and strap styles once you are comfortable with the basic construction.

Frequently Asked Questions

What fabric weight should I use?

Use fabric that weighs at least 10 ounces per square yard. Canvas, denim, and heavy cotton twill are ideal. Lightweight cotton or linen will sag under weight. If you are unsure, ask the fabric store staff or hold the fabric up to the light—you should barely see through it.

Can I make this backpack without a sewing machine?

Yes, but it will take much longer. Hand-sewing a backpack takes six to ten hours instead of two to four. Use a needle and strong thread, and sew with a running stitch or backstitch. Reinforce all seams by sewing over them twice. Hand-sewn seams are actually very durable if you sew them tight and close together.

How do I make the straps adjustable?

Sew a plastic or metal slider onto each strap before you attach it to the backpack. The slider lets you shorten or lengthen the straps by folding the webbing back on itself. You can find sliders at fabric stores in the notions section. Sew the slider securely with a small square of stitches so it does not slide during use.

What if my fabric frays at the edges?

Fraying is normal with natural fabrics like cotton. You can seal the edges with a zigzag stitch on your sewing machine, or explore a product called fray check (a liquid that hardens the fabric edge) before you sew. Alternatively, use a serger if you have access to one. For a casual backpack, light fraying is not a problem and will fade with washing.

How do I wash my finished backpack?

Turn the backpack inside out and wash it in cold water on a gentle cycle. Air dry it flat or hanging. Do not use a dryer, as heat can damage the thread and weaken the seams. If the straps get dirty, spot-clean them with a damp cloth and mild soap.