How to Choose a Backpacking Pack: Volume, Fit & Features Guide (2026)

Your backpack is the most personal piece of gear you own. A bad fit makes every mile harder. The right pack disappears on your back. Here's how to choose one that actually works.

The Fundamental Rule

Your pack should match your load. The heavier your gear, the more support structure you need. As you go lighter, you need less — and a lighter, simpler pack becomes not just acceptable but better.

Volume: How Much Do You Need?

Volume is measured in liters.

A common mistake: Buying too large a pack and filling it. Start with the gear you have, see what volume it occupies, then buy accordingly.

Frame Types

Frameless

• No structure — pack shape determined by contents
• Lightest option (8-16 oz)
• Requires dense, well-packed gear
• Only works with light loads
• Examples: ULA Ohm, Gossamer Gear Gorilla

Internal Frame (Suspended)

• Aluminum stays or framesheet transfer weight to hips
• Best support for moderate to heavy loads
• Most common type
• Examples: Osprey Atmos, Gregory Baltoro, Hyperlite Mountain Gear

External Frame

• Rigid frame with pack attached externally
• Best ventilation, great for extremely heavy loads
• Uncommon today, mostly legacy designs

Fit: The Most Important Factor

Torso length, not height, determines pack fit.

Measure your torso: from C7 vertebra (bone at base of neck) to the top of your iliac crest (hip bones).

Many packs come in one or two torso sizes. Some (like Osprey) offer adjustable suspension.

Fitting a Pack in a Store

1. Load the pack with 25-30 lbs
2. Hip belt should sit on top of iliac crest, not waist
3. Shoulder straps should follow shoulder curves without gaps
4. Load lifter straps should pull at ~45° angle
5. Sternum strap at comfortable level across chest

80% of pack weight should ride on hips. If your shoulders hurt, the fit is wrong.

Hip Belt Width and Padding

Hip belts are size-specific. A wide hip belt on narrow hips = no support.

• Measure your hip circumference at the iliac crest
• Compare to pack's hip belt size chart
• Some packs offer interchangeable hip belts

Key Features

Back Panel Ventilation

Trampoline-style frames (Osprey's AirSpeed, Deuter AirContact) hold the pack away from your back for airflow. Worth it in hot climates. Adds weight.

Pockets

• Hip belt pockets: essential for snacks and phone access
• Side pockets: water bottles, should be accessible without removing pack
• Top lid: frequently accessed items
• Front shove-it pocket: wet/dirty gear

Compression Straps

Cinch the pack down when not full. Critical for a well-fitting load on short trips.

Hydration Compatibility

Most packs have a sleeve for a hydration reservoir. Useful but heavy — some ultralight hikers skip bladders entirely and use bottles.

Rain Cover

Many packs include one. A pack liner (trash compactor bag) is lighter and works better.

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