A man will tend to burn more calories than a woman of the same height, weight, and age. But we are talking only a small percentage.  A 30 year old, 5'8", 180 pound woman has a computed BMR of 1616 cal/day, a man with the same stats would be 1847. I don't know how accurate these online calculators are, so the numbers could be off. I actually thought the difference would be less.