Check the box for the items you intend to carry with you on the trek. If left unchecked, the value will not be computed in the total. All the weights shown are averages for these items but if you know the exact weight of the item you're carrying, you can overtype the weight in the box. If you're carrying multiples of an item (e.g., two pairs of socks) overtype and double the weight shown. The goal is to keep your total pack weight down to 25-30% of your body weight. Good luck!