That one website that adds up the weight of everything in your pack so you can pack lighter

LighterPack lets you list every item with its weight, marks what is worn or consumed, charts where the weight goes and gives you a link to share the list. It is free but you need an account (email, username and password) to save lists; it is the standard tool in ultralight hiking and one-bag travel circles, which is why it is the pick despite the signup.