For day hikes, 18 to 28 liters holds water, food, a rain jacket, a warm layer and a first aid kit. For one or two nights, 40 to 55 liters is usually enough with modern gear. For three nights or more, or bulky winter gear, look at 55 to 70 liters.
Buying a pack a little too big is a common first mistake: it gets filled, and then it gets heavy.
How should a hiking backpack fit?
Torso length matters more than your height. Most of the weight should ride on the hipbelt, which sits on top of your hip bones, with the shoulder straps wrapping your shoulders without gaps. Many packs come in sizes or adjust, so measure your torso before you order.
Questions
Hiking Packs FAQ
Is a 20-liter backpack big enough for a day hike?
For most day hikes in warm weather, yes. Move up to 24 to 30 liters for cold weather, when layers take more room, or if you carry for a child or a partner.
Do I need a hydration vest or a daypack?
A vest if you run or move fast and want water you can reach without stopping. A daypack if you hike at a walking pace and carry more layers and food. Our Basecamp piece on vests vs backpacks walks the decision.
Are Osprey packs worth it?
Osprey dominates our pack rankings because its packs fit a wide range of bodies, adjust well, and come with a strong lifetime repair guarantee. Cheaper packs from other brands work, but often fit fewer torso lengths.
By Tom. Picks are ranked from published specs, Amazon buyer reviews and AI-assisted research, never paid placement. Ratings are as last checked on Amazon, which always has today's price.
