Step 1: Place the end of a soft tape measure at the centre of your forehead about 2cm above your brow line.

Step 2: Wrap the tape around your head, keeping it straight and level. It should sit about 1cm above your ears and rest on the natural bump at the back of your head. Bring the tape back to your forehead so that the ends meet.

Step 3: Hold the tape snug to mimic how a hat would sit on your head recording your measurement. The average size for an adult is 57cm, but you may have a smaller head around 55cm or a reading of 60cm or more.

Step 4: Measure twice to be sure. If the numbers differ slightly, go with the larger measurement for comfort.