How to Choose a Backpack: The Only Guide You Need in 2026

Updated June 2026.

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Buying the wrong backpack is one of those mistakes you don’t notice until you’re three hours into a hike with numb shoulders. The straps dig in, the weight sits wrong, and you spend the rest of the trip adjusting something that was never going to work. Most people pick a backpack based on looks or price and skip the parts that actually matter.

This guide covers what to check before you buy: capacity, materials, fit, suspension, and travel style. Get these right and the backpack disappears on your back. Get them wrong and you’ll feel every mile.

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Start with Capacity: How Much Do You Actually Need?

Backpack capacity is measured in liters, and the number you need depends on what you’re carrying and for how long. A 20-liter daypack handles a water bottle, jacket, and snacks. A 40-liter pack covers a long weekend. Anything above 60 liters is expedition territory: multi-day treks where you’re hauling a tent, sleeping bag, and cooking gear.

The mistake most travelers make is going too big. A half-empty 65-liter pack shifts its weight around with every step, which means more strain on your hips and shoulders. It’s also an invitation to overpack. A snug 40-liter bag forces you to think about what you actually need, and that discipline pays off at the airport and on the trail.

Here’s a rough breakdown by trip length:

• Day trips (under 20L): commuting, sightseeing, short hikes
• Overnight to 3 nights (20-45L): weekend trips, hostel travel, carry-on flying
• 3-5 nights (45-65L): backcountry camping, extended travel with gear
• 5+ nights (65L and up): thru-hiking, winter camping, gear-heavy expeditions

If you’re mostly doing city travel and flying carry-on, a 30-40 liter range hits the sweet spot. You can fit 4-5 days of clothes, a laptop, and toiletries without checking a bag.

Materials: What’s the Bag Actually Made Of?

The fabric determines how long your backpack lasts, how much it weighs, and how it handles rain. Two materials dominate the market: nylon and polyester. There’s a detailed breakdown in our nylon vs polyester comparison, but here’s the short version.

Nylon is stronger, more abrasion-resistant, and slightly more water-resistant than polyester. It costs more and fades faster in direct sunlight. Most premium travel backpacks use some variation of nylon, often ripstop nylon, which has a crosshatch pattern woven in to prevent small tears from spreading.

Polyester holds color better and costs less. It’s not as tough as nylon, but modern polyester fabrics have closed the gap significantly. Budget and mid-range backpacks lean heavily on polyester, and for casual travel it’s perfectly fine.

Then there’s Cordura, a branded nylon fabric rated by denier (the thickness of individual threads). Cordura 500D is tough enough for daily commuting. Cordura 1000D handles serious abuse. If the product listing mentions denier, higher numbers mean thicker, heavier, more durable fabric.

Beyond the fabric itself, check whether the zippers are water-resistant (YKK AquaGuard is the gold standard) and whether the bottom panel uses a reinforced material. The bottom takes the most punishment; if it’s the same thin fabric as the rest of the bag, expect wear marks within a year.

Fit: Torso Length Matters More Than Height

This is where most people get it wrong. Two people can be 5’10” and need completely different backpack sizes because their torsos are different lengths. A pack that fits your torso distributes weight to your hips instead of hanging off your shoulders, and that’s the difference between comfortable and miserable.

To find your torso length, measure from the bony bump at the base of your neck (C7 vertebra) down to the top of your hip bones (iliac crest). Most adults land between 15 and 22 inches. Our guide on measuring your torso length walks through the process step by step.

Once you know your torso measurement, match it to the manufacturer’s size chart. Most brands offer small, medium, and large in their hiking packs. Travel backpacks sometimes skip this and use adjustable harness systems instead. Fine for moderate loads, but not ideal if you’re carrying 30+ pounds.

The hipbelt matters just as much. It should sit on top of your hip bones, not your waist. When the hipbelt is right, 80% of the pack’s weight rides on your hips and your shoulders just stabilize. If you’re between sizes, go with the smaller one; a too-large pack sags and puts everything back on your shoulders.

Suspension and Comfort Features

The suspension system is the internal framework that transfers weight from the pack to your body. Better suspension means less fatigue, and it’s the main thing separating a $60 backpack from a $200 one.

Internal frames use aluminum stays or plastic sheets hidden inside the back panel. They keep the pack close to your body and work well on uneven terrain. This is what you’ll find in most quality hiking and travel backpacks.

Frameless packs save weight but offer almost no load support. They’re great for ultralight hikers carrying under 15 pounds, terrible for anything heavier. If back pain while backpacking is something you’ve dealt with, a frameless pack will make it worse.

Beyond the frame, look at the back panel. Mesh panels create an air channel between the pack and your back. You’ll notice the difference on hot days. Foam panels are more comfortable under heavy loads but trap heat. Some brands like Osprey use a tensioned mesh system that suspends the bag away from your back entirely.

Shoulder straps should be padded but not so thick they restrict arm movement. S-shaped straps follow the body’s natural curves better than straight ones. And sternum straps (the chest clip) keep the shoulder straps from sliding outward. Always use it on loaded packs.

Match the Backpack to Your Travel Style

The “best” backpack doesn’t exist in a vacuum. A photographer needs different access points than a backpacker. A digital nomad needs a laptop sleeve that a thru-hiker couldn’t care less about.

For air travel, prioritize a bag that meets carry-on dimensions (22 x 14 x 9 inches for most airlines) and opens flat like a suitcase. Clamshell or panel-loading designs make airport security faster than top-loaders where everything comes out in a pile.

For hiking and trekking, top-loading is standard. You want external attachment points for trekking poles, a rain cover (built-in or included), and a hip belt with pockets you can reach while walking.

For daily commuting, a 15-25 liter pack with a padded laptop compartment, quick-access pockets, and a clean profile works best. Overkill on straps and buckles looks out of place in an office.

For one-bag travel, the 35-45 liter sweet spot gives you enough room for a week of clothes without checking luggage. Look for compression straps that cinch the bag down when it’s not fully packed. A half-full bag without compression flops around.

Quick Pre-Purchase Checklist

• Know your torso length: measure before shopping
• Pick capacity by trip type: smaller is usually better than bigger
• Check the fabric denier: 300D minimum for daily use, 500D+ for serious travel
• Test the hip belt: it should carry weight, not just decorate your waist
• Open and close it fully loaded: access patterns matter
• Verify airline compliance: if you’re flying carry-on, measure before you pack

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