Andrea is right. Compare the physical weight of both arrows.
Generally for a hunting arrow you will want 10 grains per pound of draw weight. This is a general rule of thumb but nothing in this sport is cut in stone. I prefer hunting arrows on the heavy side(10 to 12 gpp) and learn the trajectory of those arrows through practice. A 150fps, 500 grain arrow is deadly to most North American game animal, if not to all. Putting the arrow through the boiler room is up to you. Without you, no weapon is effective.