Choosing the right size helmet is essential for your safety on the road. A helmet that's too big or too small is more or less dangerous, whether you're riding a motorbike or a bicycle. 

To determine the right size for your helmet, you need to measure your head circumference. To do this, take a tape measure or a string (shoelace) and then measure with a ruler if you don't have a tape measure. For an adult, the head circumference is between 52 and 66 cm, which corresponds to XXS to XXL. 

If you are between two sizes, go for the size below, as the helmet foam will settle over time and adapt to the shape of your face.

Some helmet models fit differently, which is why we've listed all the measurements for each bike and motorbike range below.