Find yourself surrounded by thru hikers on a long-distance hiking trail for long enough, and chances are that at least one person will mention their base weight. Having the lowest base weight can oftentimes be a friendly competition amongst the ultralight backpacking community. Less than 10 pounds is a badge of honor of sorts and one that most ultralight backpackers typically strive for. 

But what exactly defines your base weight? To put it simply, your base weight is everything that you carry in the backcountry that remains constant throughout the duration of your trip. 

Generally speaking, your base weight encompasses your ‘big three’ (backpack, tent, sleep system), extra clothes, electronics, toiletries, and any and all other ‘luxury’ personal items you choose to take with you. That flask of whiskey stashed in your pack (excluding the weight of the liquid inside the flask) should be included in your base weight calculations!

Items in your pack that are constantly fluctuating in weight and amount are not to be considered part of your base weight. For example, food and water are not calculated in your base weight, as the weight of these items is constantly decreasing/increasing throughout your trip.

The clothes that you are currently wearing while starting your hike and the socks and shoes that you wear on your feet while starting your hike are not calculated in your base weight but rather are considered ‘worn weight.’ However, all additional layers that are packed in your pack to be worn at another time should be calculated in your base weight. So, why all the fuss over some number? It’s pretty straightforward; the lower the weight of a pack, the less energy you’ll need to throw it over your shoulders and carry it over a given distance. The less energy you need to exert, the more you’ll have in the tank over the course of a day. You may still finish a day with your ass kicked, but at least it won’t be your pack’s fault. It’s simple physics, really.