Mezza, the concervative answer is, "Replace it." I agree with those before me who said to use it in lieu of NO helmet, but then relegate it to emergency use only once it is replaced. These helmets are intended to absorb the forces of a single impact and then be discarded. Of course that impact presumes your entire weight falling on it, and not just the weight of the helmet alone. Therefore, the miser in me says that the helmet has still 99% of its energy absorbing capacity intact. So balance that into the equation; but consider that your head is a lot more valuable than the helmet and that the fact that the helmet cracked suggests that it is not strong enough to rely on with your head inside, even before the drop. Is it a good brand? Is it less than five years old? Polystyrene Foam has a five year lifespan after which it can not be considered strong enough to protect you reliably, even with no collisions. How old is it anyway? If it is older than five years, it should be replaced anyway.

Better to have a cheap NEW helmet every five years than get a really expensive helmet which you rely on for 20 years because it would break your budget to replace it every five years.

Bottom line: if it cracked from being dropped just a few feet without any weight inside it, consider that a warning that it is not strong enough to be used on your head. If it is less than five years old, consider a different brand in the future. If it is older than five years, just replace it, it was past its use-life anyway, and the crack proves it.

Safe riding to you!