How to measure your head
Wrap a tape measure around your head ensuring it sits just above the ears, goes across the centre of the forehead and slightly above the eyebrows. This measurement will give you a guide to what size helmet you will need, and many now use adjustable fit systems. If you do not have a soft tape measure, you can always use a piece of string instead and measure the string against a ruler.
Ski Helmet Sizing
When considering what size to buy, it is best to use the measurements guide for reference. It is worth trying different makes and models to see which suits your head best. Some manufacturers add levels of customisation and adjustability to models for better comfort and fit.
How should a ski helmet fit?
When you try a helmet on, it should fit firmly and snugly on your head. Align the front of the helmet just above your eyebrows and tighten the chinstrap, making sure there are no unwanted gaps between the helmet liner and your head. The helmet should not press on the back of your neck, and if there is a fit system, adjust it (you should be able to tighten and loosen it slightly). If you have your goggles, then it is worth trying them on with the helmet making sure there are no big gaps where the top of the frame meets the helmet.