How to Choose a Travel Backpack (Without Regretting It by Day Two)

My first travel backpack was chosen the way I choose most things when I’m excited: quickly, and by looks. It was a 65-litre beast in a confident shade of green, and I filled it to the zipper because it was there. By day three I had learned that a pack will happily swallow every “just in case” item you own, and that a hip belt resting on your ribs is just a very expensive shoulder strap.

So how do you choose a travel backpack that won’t teach you the same lesson? Work through five decisions, in this order: how you’ll fly, how many liters you need, which frame size fits your torso, how the harness and opening style suit your trip, and whether the pack still feels good once it’s loaded.

The quick answer: For most trips, pick a 30–40 liter pack that fits airline carry-on limits. Measure your torso length (not your height) to find your size. Look for a padded hip belt that sits on your hip bones, a suitcase-style opening, and a harness that tucks away for flights. Then load it with 15–20 pounds and walk around before you commit.

The rest of this guide explains each step, including the places where popular advice goes wrong.

Where should you start when choosing a travel backpack?

Start with the pack’s job, because “travel backpack” covers at least four very different animals.

• Carry-on only travel: one bag, no checked luggage, usually 30–40 liters. This is where most trips land.
• Long-term or multi-country travel: more room for varied climates, usually 40–55 liters, often checked at the airport.
• Travel plus trekking: a pack with a real suspension system for days of walking with weight.
• City trips and short hops: a small pack, often under 30 liters, that doubles as a daypack.

Write down which one you are. Everything else in this guide gets easier once that’s settled, and most backpack regret comes from buying for the trip you imagine rather than the one you take.

How many liters do you actually need?

Capacity is measured in liters [the volume of the bag’s interior, like a water bottle but for socks], and most of us overbuy.

• Under 25 liters: a personal item or daypack. Fine for a weekend if you’re disciplined.
• 30–40 liters: the carry-on sweet spot. Enough for one to three weeks if you pack light and do laundry.
• 40–55 liters: a stretch for carry-on. Often gets checked, or squeezed into the bin on a good day.
• 55 liters and up: bulky gear, cold-weather trips, or months away. Plan on checking it.

Many guides call 50–70 liters the “sweet spot” for trips of a few weeks. For travel, that’s too much. A pack that size won’t qualify as carry-on on most airlines, and a bag always fills to its capacity, whether or not the contents earn their place. Bigger isn’t better here; it’s just heavier.

One more wrinkle: liters are a loose measure. Brands calculate volume differently, so one company’s 40L can be another’s 36L. Treat the number as a rough guide and check the actual dimensions.

Will it actually fit on the plane?

This is where liters stop mattering. Airlines don’t measure in liters. They measure inches or centimeters, and sometimes weight.

Here is roughly what to expect, though every airline differs and rules change:

• Many US airlines: a standard carry-on is typically around 22 × 14 × 9 inches (56 × 36 × 23 cm), including wheels and handles. Personal items are smaller, often around 18 × 14 × 8 inches, and some budget fares allow only that.
• Many European airlines: full-size cabin bags of around 55 × 40 × 23 cm are common, with weight limits that often sit around 7–10 kg. On cheaper fares that bag is increasingly a paid extra.
• Free personal items in Europe: this is the size that catches people out. The EU approved a reform in July 2026 guaranteeing a free under-seat personal item of up to 40 × 30 × 15 cm (about 18 liters), but it isn’t expected to apply until 2027 at the earliest, and it doesn’t make the bigger cabin bag free. Until then each airline sets its own rules: Ryanair’s free item is roughly 40 × 30 × 20 cm (widened in late 2025), easyJet’s is 45 × 36 × 20 cm, and some basic fares, such as the Lufthansa Group’s, include only the 40 × 30 × 15 cm item.

The takeaway: on a cheap European fare, a 40-liter pack is not “free.” It’s a paid cabin bag. If you want to fly on the free allowance alone, you’re shopping for an 18–20 liter pack.

Three habits save you at the gate:

1. Measure the packed bag, with side pockets full and compression straps cinched. Airlines measure the outside, including anything that bulges.
2. Check the weight limit. Some airlines weigh cabin bags and some don’t, but your empty pack’s weight eats into the allowance whether they do or not.
3. Look up your airline’s page the week you fly. Baggage rules are among the most frequently changed things in travel.

A 40-liter pack usually squeaks into carry-on limits, but “usually” isn’t a guarantee. If you fly budget airlines often, buy a pack built to a specific airline size, not just a liter count.

Why does your torso matter more than your height?

Because a backpack hangs from your torso, not your legs. That’s why a tall person with a short torso can wear a medium, and why sizing charts ask for a measurement most people have never taken.

Here is the correction to a common mistake: torso length determines your frame size (small, medium, large), not your bag’s capacity in liters. A small-framed pack and a large-framed pack can both be 40 liters. Matching a short torso to a “smaller” 30–50L pack, as some guides suggest, makes no sense. You pick the liters for your trip, then the frame size for your body.

To measure your torso length, you’ll need a flexible tape measure and a friend:

1. Tilt your head forward and find the bump at the base of your neck. That’s your C7 vertebra [the last vertebra of the neck, and the top of your torso measurement].
2. Put your hands on your hips with your thumbs pointing toward your spine, and feel the top of your hip bones. That’s the iliac crest [the bony shelf along the top of your hips]. Imagine a line running between your thumbs.
3. Have your friend measure along your spine from the C7 bump down to that line.

Retailers’ charts vary a little, but a common split runs small up to about 17½ inches, medium from roughly 18 to 19½, and large from 20 inches up, with extra-small sizes below about 16. If you land between sizes, try both. Some packs also have adjustable torso lengths, which is handy if you’re between sizes or share a bag.

Your hip size matters too. Many packs sell hip belts in separate sizes, and some have swappable ones. If the belt can’t cinch snugly around your hips, the rest of the fit won’t matter.

Should you buy a women’s-specific pack? Often, yes, though it’s worth trying both. Women’s and “short torso” versions usually have a shorter frame, narrower and more curved shoulder straps, and a hip belt shaped for wider hips. Plenty of men and women find that a pack labeled for the other group fits better, so let the measuring tape and a loaded walk around the shop decide, not the label.

What should a good harness and hip belt feel like?

Picture the weight of a loaded pack as a toddler you’re carrying for six hours. You’d want it sitting on your hips, not hanging off your shoulders. That’s what a hip belt is for.

• Hip belt: it should sit centered on your hip bones, not your waist. Padding should wrap slightly past the front of your hip bones, and it should be snug without pinching. Once tightened, it should carry most of the load. About 80 percent is a figure often cited.
• Shoulder straps: they should follow the curve of your shoulders without digging in. Test them for more than five minutes. A strap that nags in a store will shout after eight hours of walking.
• Load lifters [the small straps at the top of each shoulder strap that pull the pack closer to your back]: these fine-tune how the weight rides.
• Sternum strap: a small chest strap that keeps the shoulder straps from sliding outward.
• Back panel: mesh or channeled panels let air flow, which is welcome in humid climates. The trade-off is that ventilated panels hold the pack away from your body and add bulk, which can hurt carry-on fit.

Here’s the honest caveat that many guides skip: small travel packs often have thin hip belts. Under about 35 liters, the belt may be little more than a stabilizer. That’s fine for lighter loads, but if you plan to carry 25 pounds all day, look for a bigger, padded, weight-bearing belt.

Should you choose a panel-loading or top-loading pack?

For most travelers, panel-loading wins. A panel-loading pack [one that unzips around three sides, like a suitcase] lets you see and reach everything without unpacking from the top down. If you’re changing hostels every two nights, that matters more than almost any other feature.

Top-loading packs [one big opening at the top, closed with a drawcord and a lid] are better at keeping rain out and at carrying weight well, which is why they’re common on trek-focused bags. The downside is digging for the sock at the bottom.

A few related choices:

• Wheeled backpacks: a rolling frame with shoulder straps that tuck away. They’re heavier and less comfortable to wear, but if you mostly roll through airports and only occasionally carry, they’re a reasonable compromise. Cobblestones and stairs are their weakness.
• Stowable harness: straps and a hip belt that zip behind a panel, so they don’t get snagged by conveyor belts. Useful if you check your bag.
• Lockable zippers: worth having for night buses and shared dorms, even if a lock only deters casual thieves.

Which features are worth paying for, and which are marketing?

Worth it:

• Padded shoulder straps and a properly sized hip belt
• A separate compartment for dirty laundry or shoes
• Compression straps, which cut the bulk of a half-full bag
• A side pocket for a water bottle, and a quick-access pocket on the hip belt or lid for a phone or snacks
• A laptop sleeve, if you carry one
• Tough fabric and sturdy zippers [YKK is a well-known zipper maker, and a good sign when you see the name]

Probably overkill:

• Seventeen zippered compartments
• Color-coded organizational systems
• Pockets for things you’ll never separate
• Built-in rain covers that never quite fit (a separate pack cover often works better)

Remember that water-resistant isn’t the same as waterproof. A water-resistant fabric sheds light rain, but heavy downpours soak through seams and zippers. Use a pack liner or a dry bag for anything that mustn’t get wet.

Also pay attention to the empty weight of the pack. Heavy, over-built bags eat into your airline weight limit before you’ve packed a single sock.

How do you test a backpack before you buy it?

Never judge a pack empty. An empty backpack tells you nothing about how it carries.

1. Load it. Add 15–20 pounds. Most outdoor stores have sandbags or weights for this, or bring your own stuff.
2. Tighten the hip belt first, then the shoulder straps, then the load lifters. Fit takes ten to fifteen minutes to dial in.
3. Walk. Go up and down stairs, bend over, reach for something on the floor. The pack should feel balanced, not like it’s pulling you backward or sideways.
4. Pay attention to pressure points. A little discomfort in the store becomes real pain after a few hours.
5. Test at home. If you order online, load the pack with your actual gear and wear it around the house or on a long walk before the return window closes. Check the return policy before you buy.

How much should a travel backpack cost?

Most good travel backpacks land somewhere between $100 and $300, depending on materials, brand, and features. Prices vary and sales are common, so treat that as a rough range, not a rule.

Spend more if you travel often, have back problems or unusual fit needs, or do serious outdoor activity alongside regular travel. A well-fitted pack with a good warranty can last for years.

Save money if this is your first big trip, you’re not sure what you prefer, or you travel only occasionally. A mid-range pack from a reputable brand will usually outlast the trips you take with it.

What changes if your trip includes a trek?

Plenty of travelers combine a city trip with a few days of walking, and Nepal is a good example. A standard travel pack handles the city days in Kathmandu and Pokhara just fine. The trail is a different story.

On many Nepal treks, porters carry your main bag, and agencies tend to cap porter loads well below what a full-size backpack holds. Domestic flights to mountain airstrips such as Lukla commonly have strict weight limits too, often around 15 kg in total, so confirm the current figure with your airline or agency. The usual solution is a small daypack (20–30 liters) for water, layers, and valuables, plus a duffel for the rest. A simple setup is to leave your travel pack with spare clothes at your Kathmandu hotel and take only what you need.

If you’re doing the trek solo and carrying everything yourself, you’ll want a proper trekking pack with a real suspension system, not a travel pack with a token hip belt.

So, which travel backpack should you choose?

Put it all together and the decision gets a lot smaller. If you’re flying carry-on only for one to three weeks, you want a 30–40 liter panel-loading pack that fits your airline’s dimensions, with a padded hip belt. If you’re away longer or crossing climates, go to 40–55 liters, add a stowable harness, and find the discipline to leave half your “just in case” pile at home. For city breaks and short hops, stay under 30 liters and keep it light. And if trekking is on the itinerary, buy a trek-ready pack with a real suspension system and bring a daypack for the city days.

Measure your torso, check the airline’s numbers, load the pack, and walk around. None of it takes long. A few minutes of fuss now beats days of sore shoulders later, and a good pack, once you find it, is one of the few things in travel that gets better the more you use it.