How to Choose a Hiking Backpack? | Fit First, Then Capacity

A backpack that doesn’t fit turns a beautiful trail into a painful march. Most people pick packs by height or by the biggest trip they can imagine, and both lead to sore shoulders and wasted money. The real process is simpler: measure your torso, match the liter size to what you’ll actually carry, and check the fit with weight in the pack before you head out.

Measure Your Torso, Not Your Height

Your height tells you almost nothing about which pack fits. Torso length does, and it takes about 30 seconds to measure. Tilt your head forward and find the bony bump at the base of your neck — that’s your C7 vertebra. Place the tape measure there and run it down your spine to the point where an imaginary line across the tops of your hipbones crosses your spine. That number is your torso length.

Pack sizes vary by brand, but common ranges are: Extra small up to about 15 inches, Small from 16 to 17 inches, Medium/Regular from 18 to 19 inches, and Large/Tall from 20 inches and up. Always check the manufacturer’s size chart for the specific model — a “Medium” in one brand may not match another.

Pick Capacity By Trip Length and Gear

The volume you need depends on how many nights you’re out and how much bulk your gear takes. Buying a 90-liter pack for weekend trips means you’ll carry unnecessary weight and fight to keep things from shifting. These general guidelines work for most hikers:

• Day or overnight: 20–50 liters
• Weekend (2–3 days): 40–55 liters
• Multiday (4–7 days): 55–70 liters
• Extended or winter expeditions: 70–90 liters

Size the pack to the gear you own, not the gear you might buy. A smaller, well-packed load is more stable and easier to carry than a half-empty giant bag.

Test the Fit With Weight — And Adjust It Right

About 80 percent of the pack’s weight should sit on your hips, not your shoulders. An empty pack feels comfortable on any back; the real test needs at least 15–20 pounds of gear inside. Stuff a sleeping bag, food, water, and a stove into the pack, then put it on and tighten the hip belt first so it sits just above your hipbones. Only then adjust the shoulder straps so they connect about an inch or two below your shoulder caps, followed by the chest strap and the load lifters at roughly a 45-degree angle. Walk around your house or neighborhood for at least 10 minutes — any pressure points or shoulder strain will show up fast.

If you’re shopping for a women-specific model, our women’s day hiking backpack roundup covers tested options with proper torso sizing and hip-belt fit.

Common Mistakes That Ruin a Hike

The most frequent error is choosing a pack by height instead of torso length. Tall people can have short torsos and vice versa. Other traps: buying too much capacity for your actual load, evaluating fit without weight inside, letting the shoulder straps carry the load instead of the hips, and assuming a model you like comes in your torso size after you pick the volume. Always confirm the model’s size availability before you buy — most brands offer at least two torso ranges per pack line, but not all.

Pack Smart, Carry Easier

Where you put things matters almost as much as the pack itself. Your sleeping bag and anything you only touch at camp goes at the bottom. Heaviest items — water, food, stove, cook set — go in the middle, pressed close to your spine for stability. Bulky, rarely used gear stays at the bottom of the main compartment; lighter items you grab often, like a rain jacket or snacks, ride at the top. This keeps the center of gravity low and close to your back, which reduces sway and fatigue over miles.

FAQs

What torso length do most men and women need?

Most men fall into the 18–20 inch range, which corresponds to a Medium or Large pack. Most women have torsos between 15–17 inches, fitting Small or Medium packs. But individual variation is huge — always measure rather than guessing by gender.

Can I use a hiking backpack for travel?

Yes, but expect trade-offs. A hiking pack opens from the top and lacks the full-zip access of a travel bag, which makes digging for items frustrating in an airport. Internal pockets and organization are also simpler. For mixed use, look for a panel-loading hiking pack or a travel-specific convertible model.

How do I know if the hip belt is the right size?

The padded part of the hip belt should wrap around your hipbones without overlapping more than a few inches when tightened. If the padding ends well short of your hipbones or the belt runs out of webbing before snug, you need a different size or brand. Some packs offer interchangeable hip belts in multiple lengths.