Field guide
Pick what you carry and see where it goes before you buy a pack. Built on the National Park Service's Ten Essentials, REI's size guidance and Osprey's packing diagram.
Will it all fit?
The Ten Essentials come ticked, because the Park Service says to carry them on every hike. Add what else you bring and watch each piece go where it rides best.
Where things go follows Osprey's packing diagram, adapted for a day pack. Volumes and weights are rough averages for common gear, plus a quarter for the gaps between things; water counts at 1 kg per liter.
How big a pack for how long
REI's ranges, in liters. A bigger pack isn't better: it invites overpacking, and a half-empty pack rides loose.
| Liters | Good for |
|---|---|
| 10 or less | Running, short outings: a light jacket, water, a snack and keys. |
| 11–20 | Hikes of a couple of hours: an extra layer, food and day gear. |
| 21–35 | The sweet spot for most hiking and travel daypacks. |
| 36–40 | Days that need more clothing and gear, like climbing or cold-weather hikes. |
| 30–50 | Weekend backpacking, 1 to 3 nights. |
| 50–80 | Multiday trips, 3 to 5 nights. |
| 70+ | Extended trips of 5 nights or more, and winter overnights. |
Sources: REI, Daypacks: How to Choose; REI, How to Choose a Backpack.
The Ten Essentials
The National Park Service's list of what to carry on any hike, short or long. Add to it for your activity and the park you're visiting.
- NavigationMap, compass, GPS
- Sun protectionSunglasses, sunscreen, hat
- Extra clothingJacket, hat, gloves, rain shell, layers
- IlluminationFlashlight or headlamp
- First-aid suppliesA first-aid kit
- FireMatches or lighter, fire starter
- Repair kit and toolsDuct tape, knife, multi-tool, scissors
- NutritionExtra food
- HydrationWater and a way to treat it
- Emergency shelterTent, space blanket, tarp or bivy