Using a tape measure, measure the widest circumference around your head. Run the tape measure slightly above the eyebrows (typically ½"– 1"), keeping the tape measure horizontal and rounding the head above the ears. Take several measurements to ensure you have the largest circumference. Alternatively, you could use a string and measure it against a ruler. Apply your measurement to the helmet sizing chart to find your recommended helmet size. If a measurement falls in-between a size, go up to the larger size.