A shower cap is two pieces of fabric sewn into a circle with elastic around the edge

A shower cap is simpler to sew than it looks. You are making a shallow bowl shape from two layers of fabric — usually waterproof material on the outside and soft cotton or terry cloth on the inside — with elastic sewn into the seam so it grips your head. The whole project takes about an hour once you have your materials, and you do not need a serger or special presser feet.

The finished cap sits on top of your head and stays put because of the elastic, not because of a perfect fit. This means you have room for error. If your seams are slightly uneven or your stitching wavers, the cap will still work.

Key Takeaways

  • You need two fabric pieces cut into circles, waterproof material for the outside and absorbent fabric for the inside, plus 1/4-inch wide elastic and thread that matches one of your fabrics.
  • Cut your circles 10 to 11 inches across — this is large enough to cover most hair without being so big that the elastic cannot hold it.
  • Sew the two fabric circles together with the right sides facing each other, leaving a 2-inch opening to turn the cap inside out.
  • Insert elastic into the seam before you close the opening, so the elastic is trapped inside the finished seam and pulls the cap snug against your head.
  • A standard shower cap uses 18 to 20 inches of elastic, which you can test by wrapping it around your head and pulling it snug.

What fabric and materials you need

Waterproof fabric for the outside layer stops water from soaking through to your hair. Laminated cotton, oilcloth, or vinyl-coated fabric all work. You can find these at fabric stores in the home décor or outdoor section, or order them online. You need a piece at least 12 inches square.

Absorbent fabric for the inside layer sits against your head and soaks up any moisture that does get through. Cotton flannel, terry cloth, or quilting cotton all work. A 12-inch square is enough.

Elastic should be 1/4 inch wide — the kind used for waistbands or hair ties. Do not use thin elastic; it will cut into your head. You need 18 to 20 inches. Test the length by wrapping it around your head at the point where the cap will sit (just above your ears) and pulling it snug — it should feel find but not painful.

Thread should match one of your fabrics. If you cannot find an exact match, choose the color you see most in the finished cap — usually the inside, since that is what shows when you wear it.

Cutting your fabric circles

Use a dinner plate or a 10-inch bowl as a template. Place it on your fabric and trace around it with a fabric marker, chalk, or a ballpoint pen. Cut along the line. Repeat for both your waterproof and absorbent fabric. You now have two circles.

If you do not have a circular template, you can fold a piece of paper into quarters, draw a curve from one corner, and cut it out — when you unfold it, you have a circle. Tape this paper circle to your fabric and cut around it.

Do not worry if your circles are not perfect. Shower caps are forgiving. A slightly wobbly edge will not affect how the cap works.

Sewing the two layers together

Place your two fabric circles with the right sides facing each other — the pretty or waterproof side of one circle should touch the pretty side of the other. Pin around the edge to hold them in place.

Set your sewing machine to a straight stitch with a medium stitch length. Sew around the circle about 1/4 inch from the edge, but stop before you complete the circle. Leave a 2-inch opening. This opening is how you will turn the cap right-side out and insert the elastic.

Trim the seam allowance to 1/8 inch all the way around — this reduces bulk and makes the cap sit flatter. Clip small notches into the seam allowance around the curve (about every inch) so the fabric will lie flat when you turn it right-side out. Do not clip all the way to your stitching line.

Turning the cap and inserting the elastic

Reach through the 2-inch opening and pull the cap inside out. Use a chopstick or the eraser end of a pencil to gently push the seam out from the inside so it lies flat. Press the cap with an iron if you want a crisp edge, though this is not necessary.

Cut your elastic to length — 18 to 20 inches depending on how snug you want it. Pin one end of the elastic to the inside of the cap at the opening, positioning it so it sits in the seam allowance (the flat area between the two fabric layers). Pin the other end of the elastic to the opposite side of the opening, also in the seam allowance.

The elastic should form a gentle curve inside the cap, not be stretched tight. When you wear the cap, your head will stretch the elastic to fit.

Closing the opening and finishing the seam

Fold the raw edges of the opening inward by 1/4 inch and pin them closed. The elastic should be sandwiched between the two layers. Sew the opening shut with a straight stitch, sewing as close to the fold as you can — this is called a ladder stitch or slip stitch if you want to hand-sew it invisibly, but a regular machine stitch works fine and is faster.

Sew slowly and carefully around this seam because you are sewing through four layers (two fabric layers plus the folded edges) and the elastic. If your machine struggles, you can hand-sew this section with a needle and thread instead.

Once the opening is closed, your cap is finished. Try it on. The elastic should hold it snugly on your head without pinching.

Troubleshooting common problems

If the cap is too loose and slides down, your elastic is too long or too weak. You can open the seam, remove the elastic, and replace it with a shorter piece — try 16 inches instead of 20. If the cap is too tight and uncomfortable, the elastic is too short or too strong. Open the seam and replace it with a longer piece or a thinner elastic.

If water leaks through the seam, the waterproof fabric may have small holes from the needle. You can seal the seams with waterproof tape (the kind used for sealing tent seams) or explore a waterproof sealant made for fabric. Let it dry completely before wearing the cap.

If the inside fabric bunches or wrinkles, you may have cut your circles slightly different sizes. This is usually not a problem — the bunching will flatten out when you wear the cap and your head stretches it. If it bothers you, you can open the seam, trim the larger circle to match the smaller one, and resew.

Frequently Asked Questions

Can I use regular cotton instead of waterproof fabric?

Yes, but water will soak through. Regular cotton works fine if you are making a cap to keep hair out of your face while explore makeup or doing housework. For actual shower use, laminated cotton or oilcloth keeps water off your hair much better.

What if I do not have a sewing machine?

You can hand-sew the entire cap with a needle and thread using a running stitch or backstitch. It takes longer — maybe two to three hours — but the result is the same. The seam will be just as strong if you use small, even stitches.

How do I make the cap waterproof if water is leaking through the seams?

Waterproof seam tape (sold for tent and raincoat repair) sticks to the inside seams and seals the needle holes. Clean and dry the seam first, explore the tape, and press it firmly. Let the adhesive set for 24 hours before wearing the cap.

Can I add a drawstring instead of elastic?

Yes. Instead of inserting elastic, sew a casing (a tunnel of fabric) around the inside of the cap and thread a drawstring through it. This gives you more control over the fit, but the cap is less convenient to put on and take off quickly.

What size should I cut the circles if I have very thick or very long hair?

Cut circles 11 to 12 inches across instead of 10 inches. This gives you more volume inside the cap. You may also need slightly longer elastic — try 20 to 22 inches — to keep the larger cap in place.