How Heavy Should Your Backpack Be for Backpacking?

“How heavy should my backpack be?” has two honest answers, and budget buyers usually only hear one of them. The first is a rule of thumb tied to your own body weight. The second is a hard number the pack maker publishes and rarely markets: the max load rating. Chase only the first number and you can still buy a pack that groans under a five-day food carry. Chase only the second and you can end up hauling more pack than your base weight needs. You need both.

Base weight and total pack weight are different numbers

Base weight is everything you carry minus food, water, fuel and the clothes on your back. It is the number our roundups and builds are ranked on, because it is the part you control by buying lighter gear. Total pack weight is base weight plus those consumables plus the pack itself. On a three-night trip, food and fuel alone can add several pounds that never show up in a base-weight spreadsheet. When a rule of thumb talks about how heavy your pack “should” be, it almost always means total pack weight on your back at the trailhead, not base weight.

That distinction matters because the two numbers pull in different directions. A lighter base weight buys you more room under a body-weight rule for food and water on a longer trip. A heavier base weight eats into that room before you've packed a single meal. If you want the mechanics of lowering base weight itself, our guide on how to lower your base weight covers the gear swaps that do the most for the least money.

Water alone shows how fast total pack weight moves without touching base weight at all. A liter of water weighs about 1 kg (2.2 lb), so carrying three liters between sources adds roughly 6.6 lb that never shows up on a gear spreadsheet. Food and fuel add up the same way, day by day, which is why a rule aimed at total pack weight has to leave room for consumables on top of whatever your base weight already is. None of that changes what your pack itself is built to carry, which is the second number below.

REI's rule of thumb: about 20 percent of body weight

REI's own expert-advice guidance puts a number on it. Citing pack-fit specialist Valerie Loughney, REI states: “A loaded backpacking pack should not weigh more than about 20 percent of your body weight” and gives the worked example directly: “If you weigh 150 pounds, your pack should not exceed 30 pounds for backpacking” ( REI Expert Advice). The same page adds a day-hiking figure for contrast: a loaded day pack “should not weigh more than about 10 percent of your body weight.”

What else moves the practical number

REI, again citing Loughney, names three things beyond body weight that push the practical target around: trip duration, season and weather, and personal preference. On duration: “The longer your trip, the more food, water and fuel you'll need to carry… Even on multiday adventures, you'll still want your pack close to 20 percent of your body weight, so you'll need to be extra thoughtful about the gear and clothing you're carrying to compensate.” On season: “If you're heading out in frigid temps, you'll need to have warmer, heavier clothing and gear than if you're trekking in sunny summer weather.” And on preference, REI is blunt that some hikers “value comfort at camp and are willing to accept the inherent weight that comes with hauling in luxuries like a hammock, extra clothes and a thick, cushy sleeping pad,” while others “are OK with wearing the same clothes for days on end and sleeping on a lightweight pad” (REI Expert Advice).

Why the maker's load rating is the harder ceiling

The body-weight rule tells you what you should be carrying. It says nothing about what the pack you own can carry. Every pack maker in our registry publishes a max (or “optimal”) load rating, and it varies far more than you'd guess from price alone. Go over it and the complaint isn't comfort, it's structure: a frameless pack without back-panel support, or a frame built for a lighter carry, transfers less of that weight to your hips and more to your shoulders.

Here is the spread across four packs at very different load ratings, weights and prices:

Two things stand out. First, the cheapest pack here, the 3F UL Gear QiDian 40+16, also has the lowest rating: 3F caps it at 12 kg (26.5 lb), roughly what REI's 20% rule allows a 130 lb hiker before food and water (3F UL Gear). Second, Granite Gear's own spec sheet for the Mariposa's cousin, the Crown3 60, actually publishes three different numbers for the same pack: 25 lb without its removable frame sheet, 35 lb with it, and 43 lb with an optional aluminum stay sold separately (Granite Gear). The frame, not the fabric, is what raises the ceiling.

The Gossamer Gear Mariposa 60 is more conservative than its 35 lb max suggests: Gossamer Gear's own page recommends 30 lb as the practical load, not 35 (Gossamer Gear). The Durston Kakwa 55, at 45 lb, carries the highest rating of any pack under a kilogram in our registry thanks to its removable aluminum frame (Durston Gear), and Granite Gear's Virga3 55 sits at the other end: frameless and rated to 25 lb, with a sleeping pad doing the structural work (Granite Gear). If you want the fuller case for when a frame is worth its grams, that's a separate question — see frameless vs framed backpacks.

Even our reference pack skips the number entirely. The Osprey Rook 65 — the mainstream 65-liter framed pack every lighter pick here is measured against — weighs 1,678 g (3 lb 11.2 oz) and publishes no load range at all on its product page (Osprey). A big, heavy, traditional pack doesn't automatically tell you more than a small ultralight one does; you still have to read the spec sheet.

Some traditional framed packs do rate well past anything in the ultralight tier. The Kelty Glendale 65, at 2,150 g (4 lb 11.8 oz) with a perimeter frame and an aluminum anti-barreling stay, is rated for 30–60 lb (Kelty) — well past what a 20%-of-body-weight target asks for at any ordinary body weight, and a reminder that a higher rating isn't automatically the goal. At the other extreme, the Teton Scout 55L, at 2,041 g (4 lb 8.0 oz), publishes no load rating at all, the same gap as the Rook 65, despite being a budget framed pack built for shorter trips (Teton). Reading the spec sheet, not the price tag or the liter count, is the only way to know which you're buying.

What this means for a budget kit

Put the two numbers to work in order, rather than picking a pack off one figure alone:

1. Weigh yourself and apply REI's roughly-20% guideline to get a target total pack weight for the kind of trip you actually take. Write the number down; it's the ceiling everything else has to fit under.
2. Add your likely food, water and fuel for the length of trip you take most often. That consumable weight still has to fit inside the 20%, which is exactly why lowering base weight matters more the longer your trips run — there's less room left for anything else once food and fuel are accounted for.
3. Check the pack's own load rating separately against that same total, not just your base weight. A pack can sit comfortably under REI's body-weight target and still be overloaded by its own maker's number, especially a frameless one carrying a multi-day food bag.
4. Buy some headroom, not the exact number. A pack rated a few pounds above what you'll actually carry tolerates a cold-weather trip, an extra day of food, or gear you add later, without changing packs.

For most budget buyers building toward a lighter kit, that argues for a pack rated comfortably above what you'll actually carry rather than right at the edge of it. Our best budget ultralight backpacks roundup ranks the full field by grams saved against the Osprey Rook 65 reference, with the load rating listed on every card so you're not guessing.