Things You'll Need
Double fold bias tape
Reducing the size of a wide brimmed hat may sound as simple as taking a pair of scissors to the hat and trimming it down to size, but doing so will leave you with a raw edge. This edge usually will not enhance the appearance of the hat, and it may cause the hat to unravel and fall apart much sooner than it would have normally. Fortunately, creating a finished edge does not require a great deal of time or skill.
Mark the brim of the hat with a piece of chalk or a fabric marking pen to determine the size you want the finished brim to be. Examine the line you have created and make sure you are satisfied with it as you will not be able to make the brim larger if you change your mind.
Carefully cut the brim along the line you created with scissors.
Try the hat to determine if you are satisfied with the new size of the brim, or if you would like to reduce it even more. If you want the brim even smaller, cut it to the correct size at this time.
Apply double fold bias tape to the raw edge of the hat's brim. This tape is available in a wide variety of colors and is folded slightly off-center. Make sure that the longer side of the tape is underneath the brim with the shorter side of the tape on top of the brim.
Secure the binding tape in place with small pieces of clear tape.
Sew the bias tape onto the brim of the hat with a sewing machine. Use a straight stitch and sew very close to the inner edge of the bias tape all the way around the brim of the hat. If you placed the longer side of the tape under the hat, you can be confident that the underside of the tape is also being sewn to the hat as you work.
Secure the seam by back-stitching two, or three times at the end of the stitch. Snip any loose threads and enjoy your new smaller hat.
You can sew directly through the tape used to hold the bias tape in place, but it may cause your sewing machine needle to become sticky and distort stitching. For better results, remove the small pieces of tape as your needle draws near to them.