The So-Called 10% Rule


The “10% Rule” . . . when it comes to pack weight considerations, probably no guideline is more cited (and disputed!) in Camino forums. What is the 10% Rule, and is it based on science, folk wisdom, or mere rumor?


Problems with the 10% Rule

This popular pack weight rule of thumb says that you should not carry more than 10% of your body weight in your kit. As far as guidelines go, it’s OK . . . I guess . . . but as a rule, it’s significantly flawed. There are far too many factors that go into a body weight / pack weight equation for such a simple figure to function as a rule.

Here are four reasons why the 10% Rule for backpacking doesn’t work (any one of which is sufficient to make the case):

First, body weight does not indicate body fitness.


Two people of identical body weight could differ wildly as to packing ability because body weight could be based on flab or muscle or height or bone density, etc. None of these are equivalent when it comes to carry capacity. Cardio and endurance levels dramatically play into the overall outcome as well, not to mention experience and skill. All of these factors (whether considered individually or combined) are more important than a simple weight ratio (which, ironically, favors people who are overweight).

Second, pack weight is affected by pack quality.

CvsE.JPGThis point is true in both directions. Here, a more useful rule of thumb comes into play: Between light, cheap, and quality, you may pick two. A cheap backpack with a good suspension system might weigh several pounds more than an expensive lightweight pack – but it would be better for carrying heavy loads than a cheap lightweight pack with a crappy suspension system (see the fourth point below). This means that sometimes total pack weight can be offset by a good suspension system, which actually makes the heavier total weight safer to carry.


Note that ultra lightweight packs often cut weight by reducing their suspension system. They can get away with this because the packs are designed for light pack loads in the first place. Thus, the perceived carry weight may be higher in packs that actually weigh less (especially for folks with bad backs).

Third, small hikers can carry more than large hikers.


In fact, percentage-wise, smaller hikers can carry a lot more. This has been demonstrated by actual science. While this might go against intuition, it actually makes a lot of sense when we consider more extreme examples of strength-to-weight ratios (e.g., ants). Our muscles carry our total weight, not just our pack weight – and strength generally increases more slowly than body weight. Thus, a fit 100 pound person can carry a 25 pound pack easier than an out-of-shape 250 pound person can carry a 10 pound pack (or no pack!).

Fourth, the actual studies are irrelevant to backpackers.


When the 10% rule is backed up by actual studies, the data has almost nothing to do with legit backpacking. Rather, it seems to be based on children’s book bags (example). The findings of these studies do not apply to full-sized packs, though, because book bags (and many day packs) put 100% of their weight on the shoulders/back, whereas hiking backpacks should transfer at least 80% of their weight to the hips. Further, book bags are typically used to carry . . . books. Unlike tents, sleeping bags, clothing, etc., books simply do not ride well in a non-cushioned pack.


The so-called 10% Rule simply does not apply to backpacking or the typical Camino pilgrimage. In fact, it’s questionable if it is even useful as a rule of thumb. While there is nothing wrong with starting off with an arbitrary weight ratio goal, elevating it to the level of rule is unrealistic, unhelpful, and possibly even dangerous. (For example, imagine someone leaving behind a 1 liter bottle of water because it “used up” 25 pounds of their body weight!)

Bring what you need – and if what you need is too heavy to carry, change your plans.


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