How to Choose a Backpacking Backpack? | Fit and Volume First

The wrong backpack can turn a weekend in the woods into a sore, exhausting ordeal. Most people start with height or price, but the two numbers that actually matter are liters (how much gear fits) and torso length (how the weight rides). Get those right, and the rest—features, fabric, frame type—falls into place.

Start With Trip Length: What Volume Do You Need?

Backpack volume is measured in liters, and the right range depends almost entirely on how many nights you plan to carry your gear. A day pack won’t hold a tent; an expedition pack is overkill for an overnight trip.

A 50–60 liter pack weighing around 4 pounds hits the sweet spot for most multi-day trips, balancing capacity, weight, and cost. If you tend to pack light, lean toward 50; if you bring extras, 65 gives breathing room.

Forget Height: Measure Your Torso Instead

Two people who are both 5’10” might need different pack sizes. The critical measurement is torso length—the distance from the bony bump at the base of your neck (C7 vertebra) to the top of your hip bones (iliac crest). Most adult torso lengths fall between 16 and 21 inches.

Here is how to measure yours, following REI’s official fit guide:

1. Tilt your head forward and feel for the prominent bump where your neck meets your shoulders—that is C7.
2. Slide your hands down your ribcage until you feel the top ridge of your hip bones. Draw an imaginary line between your thumbs across your lower back.
3. Have a friend measure the distance in inches between C7 and that imaginary line.

Once you have that number, a pack’s manufacturer size chart (small, medium, large) tells you which torso range fits. Most outdoor stores also let you test the fit with a weighted pack before you buy.

How to Verify the Fit (The Real Test)

Load the pack with 15–20 pounds of gear or packed blankets. Then run through this checklist:

• Hipbelt position: The padding should sit squarely on top of your iliac crest (the top ridge of your hip bones), with the belt’s curve hugging your hips. The hipbelt should carry most of the weight.
• Shoulder straps: The anchor points where straps attach to the pack should sit 1–2 inches below the top of your shoulders. Straps should curve gently around your shoulders without gaping or digging in.
• Load lifters: These small straps near your collarbones should form a 30–45 degree angle to the pack. Tighten them gently—overtightening pulls the pack away from your back.
• Sternum strap: Position it about 1 inch below your collarbones. Snug it just enough to stabilize the shoulder straps, never so tight that it restricts breathing.
• The gap test: If a large space opens between your back and the pack frame, the torso is too long. If the shoulder straps squeeze your armpits, the torso is too short.

What to Look For in Materials and Features

Once the size is right, check these specs before committing:

Choosing Between Ultralight and Standard Packs

A standard backpacking pack supports 20 to 40 pounds of gear comfortably, with a padded frame and hipbelt designed for heavier loads. Ultralight packs trim weight by using thinner fabric and a simpler frame, but they top out around 30 pounds of total gear weight. If you carry a stove, full tent, and extra layers, stick with a standard pack. Ultralight works best for experienced hikers who have already cut every unnecessary ounce from their kit.

The gear you choose to carry inside the pack matters just as much. Once you know your volume and fit, a thoughtful equipment list makes every step easier. Our guide to top-rated backpacking equipment and gear walks through the tent, sleeping bag, stove, and other essentials that match your pack’s capacity.

Common Fit Mistakes That Ruin a Hike

• Choosing by height: Two people at 5’8″ can need different torso sizes. Measure instead of guessing.
• Volume too small or too large: An undersized pack won’t hold your gear; an oversized one adds weight and encourages overpacking.
• Overtightening straps: A cranked hipbelt pinches your hips. Overtightened load lifters pull the pack away from your back. A snug sternum strap restricts breathing.
• Buying for light loads with a heavy pack: A durable 5-pound pack is miserable on a 15-pound carry. Match the pack’s frame to your expected load.
• Skipping the in-store test: Brands fit differently—treat packs like shoes. Load one up at the store before deciding.

How Much Weight Should a Backpacking Backpack Carry?

A healthy adult can comfortably carry 35 to 40 percent of their body weight. Experienced hikers push toward 40–50 percent on short trips. For newer backpackers, a target total pack weight of 20 to 30 pounds (including food and water) keeps the trip enjoyable and reduces strain on knees and shoulders. Estimate about 2 pounds of food per day and 35 ounces of water per liter when calculating your final load.

Brands shift their sizing slightly, so the torso measurement you took earlier is the single tool that converts a good pack into a great one for your body.

How to Choose a Backpacking Backpack: Final Checklist

• Decide your typical trip length and pick a volume range (40–55L for weekends, 55–70L for weeklong trips).
• Measure your torso length from C7 to your iliac crest.
• Look up the pack’s size chart and select the torso range that matches your measurement.
• Test-fit the pack with 15–20 pounds: hipbelt on hip bones, shoulder straps 1–2 inches below shoulders, load lifters at 30–45 degrees.
• Choose 400-denier fabric or higher, internal frame, and padded hipbelt.
• Consider total pack weight: 20–30 pounds for newer hikers, up to 40 pounds of body weight for experienced trekkers.