Base Weight Explained: What It Is and How to Calculate It
If you've spent any time around ultralight hiking, you've heard the term "base weight." It's the single most useful number in your kit — more useful than total carried weight, more useful than pack volume, more useful than the price you paid.
But most beginners get it slightly wrong on first attempt, usually by accident, and the wrong number leads to wrong conclusions about their kit. This guide walks through exactly what base weight is, how to calculate it, what numbers to compare yourself to, and what to actually do with the result.
It's a short concept. The whole article is built around making sure you get it exactly right.
The Definition
Base weight is the total weight of everything you carry on a hike, except consumables.
Consumables are the things you eat, drink, or burn through during the trip:
- Water
- Food
- Fuel
- Maybe also small disposables like toilet paper and sunscreen (these are usually included, but some hikers exclude them — see below)
Everything else — your pack, your shelter, your sleep system, your clothes (the ones you're not wearing on the body), your stove, your electronics, your first aid, your tent stakes — counts toward base weight.
The clothes on your body when you start walking are not in base weight. Neither are your trekking poles if you're holding them.
Why Base Weight, Not Total Weight?
Total carried weight changes constantly during a hike. You drink water and total weight drops. You refill at a stream and it goes back up. You eat dinner and weight drops again. Total weight on day 1 of a 7-day route is wildly different from total weight on day 6 of the same route, even though your kit is identical.
Base weight is stable. It's the weight you committed to when you packed your bag. It's comparable between hikers, between routes, between seasons.
It also lets you have meaningful conversations: "My base weight is 7.2 kg" is a number that means something. "My pack weighs 11 kg when I leave the trailhead with five days of food" means almost nothing — because consumables vary by hiker, by season, by water availability.
How to Calculate It
The mechanical part is straightforward:
- Weigh every item individually. A small kitchen scale (€15 on Amazon) does it. Down to the gram if possible.
- Categorize each item. Shelter / sleep / pack / clothing / kitchen / navigation / first aid / electronics / hygiene / miscellaneous.
- Sum everything except consumables. Water, food, fuel, daily-consumed disposables stay out.
That's the formula. Total minus consumables equals base weight.
In practice, the friction is the first step: weighing everything is tedious and most beginners skip it for the items they "know" the weight of. Then their base weight calculation is wrong by 300–500 g without them realizing it. Always weigh. Don't trust manufacturer specs — most are optimistic by 5–15 %.
Track it in a spreadsheet, in Gearshack, or — for a one-off — on paper. The tool doesn't matter as long as you're honest with the numbers.
The Gray Areas (and How to Handle Them)
A few items don't fit neatly into the "consumable" / "not consumable" split. The community has converged on conventions for these, but you should at least know the choices:
Toilet paper. Consumable. You burn through a roll on a long route. Exclude from base weight.
Sunscreen, bug repellent, hand sanitizer. Mostly consumed during the trip. Convention: exclude from base weight, count as consumables.
The clothes you're wearing. Not in base weight. You're carrying them on your body, not in your pack.
Clothes in your pack that you'll wear if it gets cold. In base weight. They're packed gear.
Trekking poles. This one is contested. If you carry them in your hands the whole time, they're not in base weight. If they're sometimes strapped to your pack, they sometimes are. Most hikers count them as base weight for simplicity.
Your phone. Yes, in base weight.
Your shoes. Not in base weight. Worn weight.
Worn weight (sometimes also called "skin out weight") is a separate, useful number — total weight including everything on your body. Less commonly discussed than base weight, but increasingly used in ultra-light circles.
What Numbers Should You Compare Yourself To?
Rough orientation for 3-season European hiking with a competent kit:
| Base weight | Category |
|---|---|
| Under 4 kg | Sub-ultralight (SUL) — experienced, premium gear |
| 4–5 kg | Ultralight (UL) — serious optimization |
| 5–8 kg | Lightweight — most committed hikers land here |
| 8–12 kg | Conventional — room for optimization |
| Over 12 kg | Heavy — significant savings available |
These are 3-season targets. Winter or alpine shoulder season legitimately adds 1.5–3 kg for insulation, traction, and shelter. A 9 kg winter base weight is not the same as a 9 kg July base weight.
Don't chase a target number for its own sake. A 5 kg base weight that doesn't include adequate insulation for your route is worse than an 8 kg base weight that does. Base weight is a measurement, not a goal.
A Worked Example
Here's a real 3-season solo Alpine hut-to-hut kit, calculated from scratch:
| Item | Weight (g) |
|---|---|
| Pack: HMG Windrider 40L | 844 |
| Shelter: Lunar Solo + 6 stakes | 790 |
| Sleeping bag: Cumulus X-Lite 400 | 575 |
| Sleeping pad: Therm-a-Rest NeoAir XLite | 354 |
| Insulation: Patagonia Down Sweater | 390 |
| Rain shell | 240 |
| Wind shell | 130 |
| Spare base layer + socks | 280 |
| Trekking poles (in pack on flats) | 400 |
| Stove + windscreen + lighter | 70 |
| Pot: MSR Titan Kettle 850 ml | 118 |
| Cup + spork | 60 |
| Water filter: Sawyer Squeeze | 105 |
| Bottles: 2× 1L Smartwater | 70 |
| Headlamp + spare batteries | 75 |
| Phone | 180 |
| Powerbank 10000 mAh | 195 |
| Maps + compass | 90 |
| First aid kit | 180 |
| Repair kit (tape, cord, sewing) | 60 |
| Toiletries (excl. consumables) | 80 |
| Sunglasses + case | 50 |
| Total base weight | 5.34 kg |
That's a real European Alpine 3-season kit, in the UL band. Note that consumables — typically 2.5 kg of water and 3–5 kg of food at the start of a multi-day — would push total carried weight to 11–13 kg on day 1.
What to Do With the Number
Once you have your base weight, the more useful question is: how is it distributed?
Look at the percentage breakdown by category. For a typical UL solo kit:
- Shelter: 20–25 % of base weight
- Sleep system (bag + pad): 15–20 %
- Pack: 10–15 %
- Insulation + clothing: 15–20 %
- Everything else combined: 25–35 %
If any single category is over 30 % of your base weight, that's where the next upgrade pays off most. If shelter is 30 % of your base weight, optimizing your shelter saves more weight than optimizing five smaller items.
This is the only way to make optimization decisions that aren't driven by what looks fun to buy.
Track Base Weight in Gearshack
Gearshack calculates your base weight automatically as you add gear. It shows the category breakdown, flags consumables separately, and lets you build named loadouts (summer Alps, winter Mittelgebirge, weekend trip) — each with its own base weight calculated on the fly.
Add 30 items in the first session and you'll know your real base weight by tonight — including the bits you've been guessing at.
Want to compare your base weight to other hikers in similar conditions? Public loadouts on Gearshack let you see real numbers from real kits. Sign up and start exploring.