By Dana Okoro, Editorial Reviewer · Published September 14, 2026, 6:03 PM ET · Updated September 29, 2026, 6:16 PM ET
Direct Answer
A common rule of thumb puts a loaded hiking backpack at about 20% of a hiker's body weight on multi-day trips — roughly 30 pounds for a 150-pound hiker. Day packs run lighter, typically 10–15% of body weight, since they carry no shelter, sleep system, or multiple days of food. This is a starting point, not a standard; no primary study or standards body sets it.
In plain English
There's no magic number for how heavy a backpack should be. A common tip is to carry no more than about a fifth of your body weight on an overnight trip. For a 150-pound person, that's about 30 pounds. It's a handy starting point, like a recipe that says bake for 30 minutes. You still check how it's going.
How heavy a pack feels depends on more than the scale. A pack that fits well, with the belt sitting on your hip bones, feels lighter than the same weight in a pack that fits badly. Being used to carrying a pack helps too.
Food and water are the parts that change. A gallon of water weighs about 8 pounds, so a trip with few places to refill can make your pack much heavier. The gear you always carry is the part you can make lighter over time.
The 20%-of-body-weight guideline scales the target loaded pack weight to the individual hiker rather than giving one fixed number for everyone. A 120-pound hiker targets roughly 24 pounds loaded, while a 220-pound hiker can carry closer to 44 pounds under the same rule.
Hiker Body Weight
Target Loaded Weight (~20%)
120 lb
~24 lb
150 lb
~30 lb
180 lb
~36 lb
220 lb
~44 lb
This figure covers the full loaded pack — base weight plus food, water, and fuel — not base weight alone. A hiker can hit a low base weight and still land near 20% once several days of food and a full water supply are added, especially on longer, more remote sections between resupply points.
Conditioning and fit change how much of this guideline is tolerable in practice. Fit changes how a given load feels: a well-fitted pack with the hipbelt carrying most of the load, correctly sized to torso length, feels lighter than the same weight in a poorly fitted pack, which can make even a modest load feel excessive because more of it lands on the shoulders instead of the hips.
Day hikers should target a lower percentage, generally 10–15% of body weight, since a day pack skips the shelter, sleep system, and multi-day food that push overnight loads up. Kids and youth hikers need a lower percentage still, scaled further down from the adult guideline.
The 20% figure is a widely used starting guideline rather than a strict ceiling. Base weight is the number to focus on cutting if a loaded pack consistently runs heavier than this target, since it's the only weight fully within a hiker's control before food and water are added for a given trip.
Where the 20% figure comes from, and what the research says
The 20% guideline on this page is widely repeated, but no primary study or standards body sets it; it's best read as a hiking-community rule of thumb. The published figures around it vary a lot. Deuter, a pack maker, says people can carry a maximum of 20–25% of their body weight.1 A 2022 ergonomics review says adult loads in military, hiking and mountaineering settings should generally not exceed 40% of body mass.2 A 2026 study of long-distance hikers notes the literature has suggested 10–15%, and found forefoot pressure rose 5.41% with a pack at 10% of body weight and 8.73% at 20%.3
Military doctrine sits higher. The US Army says a properly conditioned soldier's fighting load should ideally be about 30% of body weight, and an approach-march load about 45%.4 Real hikers often exceed 20% too: a 2004 study found Appalachian Trail long-distance backpackers averaged 25.0% of body weight for men and 27.9% for women.5 None of this makes heavier loads comfortable; it shows the 20% line is a sensible target, not a safety limit.
What each extra pound costs
Percentages hide a simpler fact: every bit of weight costs energy. A 2014 study found metabolic energy use during walking rose roughly linearly with backpack load, by about 7.6 watts per extra kilogram.6 UK infantry testing with 25–70 kg loads found metabolic cost rose about 1% for every additional kilogram.7 The US Army's manual states it differently, saying energy expenditure stays constant at loads up to 30% of body weight but rises through the march above that.4 Knapik's review adds that the cost also rises with walking speed and grade.8
Water is the biggest swing. The NPS at Guadalupe Mountains says water weighs about 8 pounds per gallon, and a three-day trip there at a gallon per day means about 24 pounds of water.9 On a dry route, your loaded weight can jump well past any percentage target, which is why cutting base weight gives you room when you need it.
Why fit changes the feel, and the hip-belt share is disputed
Some guides say a well-fitted hipbelt carries roughly 80% of the load. That figure comes from hiking groups and makers: the Washington Trails Association says around 80%,10 and Alpkit gives a range of 60–80%.11 The US Army's manual gives a very different split, about 30% on the hips and lower back and 70% on the shoulders with a pack frame and hip belt.4
Whatever the exact share, shifting weight to the hips helps. A study of load-carriage discomfort found the hip region tolerates pack pressure significantly better than the shoulders, and recommended moving load from shoulders to hips wherever possible.12 That's why a correctly sized pack can make the same weight feel noticeably lighter.
