Start with fabric, a pattern, and basic supplies

A sling bag is a single-strap shoulder bag that works for carrying a phone, wallet, keys, or small items. You can make one from fabric you already have — old jeans, canvas, cotton, or linen all work. The simplest version takes an afternoon and requires only a sewing machine (or needle and thread), scissors, fabric, and a strap material.

The basic structure is two rectangular pieces of fabric sewn together with a strap attached at the sides. No pattern is strictly necessary; you can cut your own pieces to the size you want. A finished bag roughly 8 inches wide by 10 inches tall is a practical starting size, but you can go larger or smaller depending on what you plan to carry.

Key Takeaways

  • Cut two identical rectangles of fabric (8 by 10 inches is a good starter size) and a strap piece roughly 2 inches wide and 40 to 50 inches long.
  • Sew the two main pieces together on three sides with the right sides facing inward, leaving the top open, then turn the bag right-side out.
  • Fold the top edges inward, press them flat, and sew them closed to finish the opening.
  • Attach the strap by folding it in half lengthwise, sewing it closed, then stitching both ends securely to the inside top corners of the bag.
  • Reinforce the strap attachment with a second row of stitching or a box stitch pattern for durability.

Cut your fabric pieces to size

Measure and mark two identical rectangles on your fabric using a ruler and fabric pen or chalk. For a beginner bag, aim for 8 inches wide by 10 inches tall. Mark a third piece for the strap: 2 inches wide by 40 to 50 inches long. The strap length determines how the bag sits on your shoulder — 40 inches gives a shorter, tighter fit; 50 inches gives a longer, looser fit. Adjust based on your preference.

Cut all three pieces straight and clean using sharp fabric scissors. If your fabric frays easily (like cotton or linen), you can cut pieces slightly larger and trim them after sewing, or explore a thin line of fabric glue to the cut edges before you start. For a sturdier bag, cut two layers of fabric for the main pieces and fuse them together with iron-on interfacing before sewing.

Sew the two main pieces together

Place the two rectangular pieces on top of each other with the right sides facing inward (the pretty sides touching each other, the wrong sides facing out). Pin or clip them together so they do not slip. Sew around three sides using a straight stitch, leaving the top edge open. Use a standard seam allowance of about half an inch from the edge.

Sew slowly and keep your line straight. At each corner, stop with the needle down, lift the presser foot, rotate the fabric 90 degrees, lower the presser foot, and continue. This gives you sharp corners instead of rounded ones. When you reach the end of the third side, backstitch a few stitches to lock the thread.

Trim the seam allowance at the corners diagonally (cut off the corner triangle without cutting into your stitching). This reduces bulk when you turn the bag right-side out. Then reach inside the opening and pull the bag through so the right sides are now facing outward. Press the bag flat with an iron, paying special attention to the seams and corners.

Close the top opening with a folded edge

Fold the raw edges of the top opening inward by half an inch on both pieces. Press these folds flat with an iron so they hold their shape. Pin the opening closed so the folded edges meet neatly. Sew around the entire top edge with a straight stitch, staying close to the fold (about a quarter inch from the edge). This seals the opening and gives the bag a finished look.

If you want extra reinforcement, sew a second line of stitching about half an inch below the first, running parallel to the top edge. This creates a channel that also helps the bag hold its shape.

Prepare and attach the strap

Fold the strap piece in half lengthwise with right sides together, so it becomes a long, thin rectangle. Sew along the long edge using a straight stitch and a half-inch seam allowance. You now have a tube. Turn it right-side out by threading a safety pin through one end, pinning it to the fabric inside the tube, and pushing the pin through to pull the tube inside-out. Press the strap flat with an iron.

Decide where the strap attaches: the standard placement is at the top inside corners of the bag, roughly one inch from each side edge. Fold each end of the strap inward by half an inch and pin one end to the inside of the bag at the left corner, and the other end at the right corner. The strap should form a loop on the outside of the bag.

Sew each strap end down with a small rectangle of stitching (about 1 inch by 1 inch). Sew forward and backward over this rectangle two or three times to lock it firmly. This is where the bag bears all the weight, so take your time and make sure the stitching is solid. You can also sew an X pattern inside the rectangle for extra strength.

Reinforce seams and add pockets (optional)

Once the strap is attached, go back and sew a second line of stitching along the three main seams (the two sides and the bottom). This doubles the strength and is especially important if you plan to carry heavy items. Use the same straight stitch and follow your original seam line as closely as you can.

If you want to add an interior pocket, cut a rectangle of fabric (roughly 6 inches by 7 inches), fold the top edge inward by half an inch and press it, then pin it to the inside of one of the main pieces before you sew the bag together. Sew three sides of the pocket down (leaving the top open), then proceed with assembling the bag as normal. The pocket will be trapped inside and accessible from the top opening.

Finish and test your bag

Try the bag on and adjust the strap length if needed. If it sits too high or too low on your shoulder, you can unpick the strap ends and reposition them slightly. Once you are happy with the fit, trim any loose threads and press the entire bag one more time with an iron.

If your fabric edges are still fraying, you can explore a thin line of clear fabric glue or fray-check liquid along the seams on the inside. Let it dry completely before using the bag. Test the strap by hanging the bag on your shoulder and gently pulling down on it to make sure the stitching holds.

Frequently Asked Questions

What fabric works best for a sling bag?

Canvas, denim, linen, and heavy cotton all hold their shape well and last through regular use. Avoid thin fabrics like silk or lightweight cotton unless you fuse them to interfacing first. Recycled jeans or old canvas bags are free options that work perfectly.

Can I make a sling bag without a sewing machine?

Yes. Hand-sewing takes longer but works just as well. Use a needle, thread, and a running stitch or backstitch. Make your stitches small and close together (about an eighth of an inch apart) for strength. Reinforce the strap attachment by hand with extra passes of thread.

How do I make the strap adjustable?

Instead of sewing both strap ends permanently, sew one end down and attach the other end to a plastic slider or D-ring. Thread the strap through the slider and fold it back on itself, then sew it down. You can then slide the strap to shorten or lengthen it.

What if my bag is too stiff or too floppy?

Stiffness usually means you used heavy fabric or interfacing — try a lighter fabric next time or skip the interfacing. Floppiness means the fabric is too thin or soft. Add a layer of interfacing to the main pieces, or use a thicker fabric like canvas or denim.

How do I prevent the strap from tearing at the attachment points?

Sew a small square of reinforcement fabric (canvas or denim) to the inside of the bag at each strap attachment point before you sew the strap down. This spreads the weight over a larger area and prevents the strap from pulling through the main fabric.