How to measure head for Bulletproof Helmet?
To measure the head circumference, you can use a standard measuring tape or a piece of string. Wrap the measuring device around your head right above your eyebrows and ears; this should be as tight as possible without being uncomfortable.
Measure the string with a ruler after marking it where it overlaps on itself. Look at this measurement to determine what size helmet you need; if it’s an odd number you should get a helmet that is one size larger for that perfect fit.
As obvious as it may seem, before you purchase a helmet or body armor you need to know what size head circumference it will fit on. If your helmet doesn’t have the perfect fit properly in the first place, then it won’t be able to protect you properly when there’s an incident.