While light weight is always a plus, it isn't necessarily the only factor to consider. The helmet's center of gravity will affect how the weight is carried, which can make a lighter weight helmet feel heavy and vice versa.
The fit of the helmet is paramount, because a proper fit will distribute the weight more evenly around the head and down through the shoulders.
Also, helmet aerodynamics are important, because a proper design will help prevent helmet lift and buffeting (which can also be exacerbated by the helmet's perceived or real weight).
When comparing helmet mass, it's important to know the size of the helmet shell used by the manufacturer. Helmet weights may vary, depending upon size. Full-face helmets range from approximately 1400 to 1800 grams.
Once helmet weight reaches about 1650 grams, it becomes harder to mask its weight. Flip-up, or "modular", helmets typically weigh more than a comparable sized full-face helmet, due to the mechanism used to flip up the visor.
Helmet manufacturers claim that Snell certification can add 50 to 100 grams or more weight to a helmet, due to the differences in the composition of the shell in order to meet Snell requirements, but modern fiber technologies may have reduced this amount -- if they're used. Also, Snell has announced an update to their standard, which may reduce this spread even further.
For the purchaser, this means that it's also important to know which helmet safety standard the helmet meets when comparing weights.
Here is a comparison chart that shows the weights of some of the helmets that we've reviewed. The helmets are listed by size. Remember, helmets should not be judged on weight alone - several other factors should be taken into consideration when choosing a helmet.