Oh boy. This opens a big can of worms.

The problem is, there is no exact, hard and fast definition of pack weight. Are you referring to "base weight" without food, fuel and water? Or the whole enchilada? In some cases base weight can be well less than half of total pack weight. Total pack weight will probably change every day of a trip but base weight will not. After 5 days your pack will not weigh the same as on the first day of a trip. That's why people draw a difference.

If it's cold and I'm wearing my 2 lb. jacket at the start, does that count into my pack weight? That's why lots of folks use the term skin out weight . That refers to everything you're wearing or carrying. IMO that's the most accurate figure. Wearing stuff or carrying it in my pockets will certainly make my pack lighter but that won't get any weight off my feet.

Sorry to be so nit picky. But this is a lightweight board where grams are lovingly counted, divided and sub divided. If you are more specific, I think I can give you a better idea of what you're looking for.