I am eager to go mountain climbing but cannot carry heavy backpacks because of my light weight. I want to know if there is any scientific equation to help me know how much weight is safe for me to have on my back.

  • A formula which shows relation between these two factors according to Physiology science.
    – user37324
    Commented Feb 9, 2013 at 16:49
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    I don't think such a relationship exists. There are too many localized variables, such as fitness, build type, bone and muscle density, health/state of your joints (knees in particular), etc. that will change the answer for each person. More important would be to learn to recognize when you're carrying too much and how to act on that knowledge.
    – Nisan.H
    Commented Feb 9, 2013 at 22:15
  • A related topic (how to get bigger and stronger) is often discussed at the fitness.stackexchange.com site. This question may be relevant to you: fitness.stackexchange.com/questions/6828/…
    – DavidR
    Commented Feb 9, 2013 at 22:47
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    If all you want to do is know how much you can carry at your current level of fitness, the best way to figure that out is to field test it - go on a series of training hikes with increasing amounts of weight, and see how you do.
    – DavidR
    Commented Feb 9, 2013 at 22:57
  • 4
    I'm sorry, but I can only refer you to the comment @Nisan.H made above me here... what you're asking for doesn't exist, and what you need to learn to do is learn how much you can carry, and how to tell when you're carrying too much.
    – DavidR
    Commented Feb 9, 2013 at 23:07

5 Answers 5


I am a decent climber and a better scientist, and I strongly suspect there is no scientific answer to your question.

I have been on my long climbs and backpacking trips where I had to carry a pack. The most important factor in how much weight I (or my friends) carried was not height, weight, or gender, it was fitness.

Your strength, endurance, and your experience carrying weight will determine how much weight you can carry comfortably.

I know this is probably not what you wanted, but I believe it is correct.

  • 3
    +1 - I have some friends much lighter than me who are much fitter, and can therefore carry greater weight for longer. I have some who are strong, but not fit, so although they can carry heavy packs, they can't travel long distances with them.
    – Rory Alsop
    Commented Feb 10, 2013 at 11:36
  • I'm curious about this. I saw your profile and read your post and it shows that you do both computer programming/science type stuff AND the mountain climbing/athletic stuff instead of just one xor the other. What happens if you just do one xor the other? Is it BAD to do just one xor the other? Is it REQUIRED to do both and not just one xor the other? Commented Feb 1, 2017 at 10:46
  • @mike4ty4 I think intellectual challenges and time spent in nature are both good for the soul. I know when I am fitter I can focus longer and better at work. And I prefer to climb with people who I think are smart and focused. So there is some cross-over. But I know plenty of people who do one without the other. Those are just things that make me, personally, happy. Commented Feb 1, 2017 at 16:19

It is not your weight that is limiting your ability to carry heavy backpacks, it is your strength. You should determine your backpack weight based on strength and what you've previously carried, not your bodyweight.

  • It cannot make me sure about because I have some friends who were very thin climbers carrying very heavy backpacks but nowadays they suffer of neck and back pain and one of them has missed her life when she was descending of Everest mountain because she was very tired and then...!
    – user37324
    Commented Feb 9, 2013 at 16:56
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    You say your friends are very thin... that means they don't have a lot of muscle mass, and were either carrying a weight that was inappropriate for their strength levels, or using improper form.
    – Sancho
    Commented Feb 9, 2013 at 17:05
  • I want to know the relation between the body weight and the backpack weight for a normal person in strength according to fitness measures for mountain climbing if there is any. According to your answer there is not any relation and for example a 45 Kg climber can carry 25 weight with no exception. Am I right?
    – user37324
    Commented Feb 9, 2013 at 21:01
  • I would say, and caution that this a figure I have gathered from completely personal experience, that I can carry up to 30% of my weight comfortably while fit, and maybe 20% when I'm not fit. Now, comfort isn't always the goal, so I can actually handle a few trips where I would carry up to 50%-55% of my body weight. But I can definitely feel the strain of it. This changes dramatically with general fitness as well as particular fitness of your back and shoulder muscles.
    – Nisan.H
    Commented Feb 9, 2013 at 22:09
  • @Nisan thanks! Send it as an answer to this question. It seems reasonable and correct. Commented Feb 9, 2013 at 22:50

I used to apply the 30% rule, and for out of shape adults it works pretty well. But I worked with teenage males, ranging from the 70 lb dripping wet grade 7 to the 160 lb lean as a rake grade 12 just starting to come into his adult strength.

But in between were a bunch of butter balls. They were already carrying excess weight.

Those older boys (which we shamelessly used as pack mules on trips with the younger ones) would quite easily carry 80 lb packs. And Ive heard of climbers doing the same on journeys to base camp. Those 70 lb grade 7's didn't have much trouble with a 30-35 lb pack either.

So the rule I came up with was 50% of lean body mass. In practice we took an eyeball look and categoried like this:

Visible ribs. 50% Can see muscles, but not bones. 40% Layer of baby fat 30% Obvious Molson Muscles overhanging belt line: 25%

Small plump kids could barely carry their own clothes and gear. We made a point of finding something bulky but not massive so they would still feel like they were contributing to the group. Egg noodles and scalloped potatoes.

Once on the trip, we sometimes had to shift things around. The goal was to equalize the discomfort. This estimation rule usually meant we only had a couple of individuals whose load we had to lighten.

You can train yourself to carry heavier loads. When I was in university, I borrowed a couple of lead bricks (35 lbs each) and kept them in the bottom of my book bag. Had to restich the bag every few months -- they aren't designed for that kind of weight. I lived a mile from campus, and biked or walked to class. (Warning: Biking with a pack that heavy is very odd) The key is that you develop habits of posture that minimizes the pain.

While daily work this way is best, setting up a pack at 40% and carrying it for an hour or so at a time on walks in the park. (wear the shoes you will on the hike too.) will help, either by training you to the higher weight, or by motivating you to leave stuff at home.


Though there is no scientific answer, you can make use of some experience-based guidelines. They vary much and none is "true". There are some of our local considerations:

  1. Our club's empirical threshold is 30% of you body weight. Which simply means, that if your pack is heavier than that and you don't have much experience, you should strongly consider either removing some unnecessary items or choosing a shorter trip (so you can carry less food).
  2. Of course this varies wildly and body weight is just one of the variables, along with strengths/fitness/endurance, skll, motivation, age, sex (girls are stronger in %), backpack quality, ...
  3. In our trips you sometimes have to carry food for about 2 weeks (and all the technical and camping gear), so this 30% guideline is somtimes violated. And our fathers, when things were much heavier, used to carry as much as 50% of their weight. And sherpas routinely carry up to 100%.
  4. Backpacks do damage you health, if they are more then your personal limit. So it's wise to increase it slowly (starting from shorter/easier trips). Note, that heavy backpack needs some skill to put it on right, otherwise you can damage your back before even walking out of the door.
  5. Regardless of the limits, if you can make you pack lighter without jeopardizing safety, do it. Poetically, if you pack is 100 g heavier than your friend's, after you come to a camp after a day hike he starts to relax and you first have to run with a 10 kg bucket of water for 5 minutes.

To sum up, I wouldn't recommend having >30% on your first mountaineering trip, but you shouldn't constrain yourself within any particular "theoretical" limit. If you want to stay healthy, listen to your body.


Your backpack weight should be 20% of your body weight, and get a 30-40 litres backpack. The backpack should fit nicely on your back with it resting slightly above your butt, and it should not obstruct your head movement. Backpack weight distribution is 40% on shoulder strap and 60% on your hip strap.

  • 1
    I would suggest that whether climbing, mountaineering, or backpacking, the goal is to have the weight from your pack resting on your hips and not your shoulders. That really makes all the difference. Commented Feb 11, 2013 at 5:04
  • 20%? Yikes! Try 10% or lower. And keeping the distribution always at 40/60 is problematic. You want to vary this up and down while you walk according to what part of your body is tiring. Commented Mar 22, 2013 at 18:17
  • I agree with Hachi28, 20% max for beginners. I don't know about 30-40L, I have a 60L but carry a large bag which takes up room. So I think the more important part of the equation is the 20%. If you are well conditioned, or the hike is relatively easy, you can go up to 25%. For me, though, I just came back from a hard 2-day 15 miler and carried close to 40% and had no problems. But I'm fairly conditioned, I would not recommend that for anyone. I do like the pack to be top-heavy, and have the weight resting on the hips.
    – user11609
    Commented Dec 5, 2016 at 21:47
  • I don't know my ratios, I'm well certain it's closer to 65% or 70% on the hips, despite most of the weight at shoulder height. That means, my pack sits in the hips, and holds onto the shoulders for the ride.
    – user11609
    Commented Dec 5, 2016 at 21:47

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