How to Choose a Hiking Backpack: Fit and Volume Guide

Quick answer

Start by measuring your torso length, then match it to a pack's adjustable range. Choose volume based on trip duration: 40–50 liters for weekend trips, 60–75 liters for multi-day treks. The Kelty Glendale 65 and Trekker 65 both offer 65 liters, but their fit systems suit different body shapes.

Measure your torso length first

Your torso length is the distance from the bony bump at the base of your neck (C7 vertebra) to the top of your hip bones (iliac crest). This measurement determines which pack size—small, medium, or large—will center the load on your hips rather than your shoulders. Many hikers skip this step and end up with a pack that sags or rides too high. Use a soft measuring tape or a piece of string and a ruler.

Match volume to trip duration

Pack volume is measured in liters. A 20–30 liter pack works for day hikes. For an overnight trip, 30–50 liters is typical. Multi-day treks (3–5 days) usually call for 50–75 liters. The Kelty Glendale 65 and Trekker 65 both sit at 65 liters, which is a sweet spot for most week-long trips. If you carry bulky gear like a bear canister or winter sleeping bag, lean toward the higher end of that range.

Check the hip belt and shoulder strap fit

The hip belt should wrap around your iliac crest, not sit above or below it. The padding should cup your hip bones without pinching. Shoulder straps should curve around your shoulders without gaping, and the load-lifter straps should sit at a 45-degree angle. A pack that fits well transfers 80–90% of the weight to your hips. If the belt is too loose or too tight, look for a pack with an adjustable torso system like the Glendale 65's Fit-Plus.

Consider frame type: internal vs. external

Internal frame packs hug your back and improve balance on uneven terrain. They are the standard for most backpacking. External frame packs, like the Kelty Trekker 65, keep the load higher and farther from your back, which improves ventilation and makes it easier to lash on bulky gear. The tradeoff is that external frames can feel less stable on rocky trails. Choose an external frame if you prioritize airflow and carrying odd-shaped loads over agility.

Test with weight before you buy

A pack feels different empty than loaded. Add 20–30 pounds of soft weight (pillows or sleeping bags work) and walk around the store for 10–15 minutes. Check for pressure points on your hips and shoulders. Adjust the torso length and hip belt while loaded. If the pack still shifts or digs in, try a different model. Many outfitters have a weighted fitting station or a sandbag for this purpose.

Step-by-step: How to choose your hiking backpack

1. Measure your torso: Find the C7 vertebra and the top of your hip bones, then measure the distance between them. Common mistake: measuring height instead of torso. A tall person can have a short torso and vice versa.
2. Select volume by trip length: Day hike: 20–30 L. Overnight: 30–50 L. Multi-day: 50–75 L. Checkpoint: If you use a bear canister or bulky sleeping bag, add 10–15 L to your estimate.
3. Adjust the hip belt: Loosen all straps, put the pack on, and tighten the hip belt so it sits snugly on your iliac crest. The belt should not slide down when you walk. If it does, the pack is too large.
4. Tighten shoulder straps and load lifters: Pull the shoulder straps until they contact your shoulders, then adjust the load-lifter straps to a 45-degree angle. Your shoulders should feel minimal weight. If they hurt, the hip belt is not carrying enough load.
5. Test the pack loaded: Add 20–30 lb of weight and walk for 10 minutes. Check for pressure points and stability. A pack that fits well should not shift more than an inch when you bend forward.

Two 65-liter packs, different fit philosophies

• Glendale 65: The Glendale 65 features Fit-Plus, an adjustable torso and hip belt system designed to accommodate a wide range of body shapes and sizes. If your torso length falls between standard sizes or you share gear with family members, the Glendale 65 lets you fine-tune the fit without buying a new pack.
• Trekker 65: The Trekker 65 is an external frame pack built for excellent load carry and ventilation, with plenty of attachment points for gear. Choose the Trekker 65 if you hike in hot conditions or carry awkward items like a tent or climbing rope—the external frame keeps your back cooler and makes lashing easy.