Understanding dry bag capacity for every outdoor adventure

You have decided to buy an outdoor camping waterproof bag. But when you start shopping, you are confronted with a dizzying array of sizes—2L, 5L, 10L, 20L, 30L, 40L, 50L, even 100L+. What do these numbers mean in the real world? And how do you know which size is right for your camping trip?

This guide breaks down exactly what each liter capacity holds, what activities each size suits best, and how to choose without wasting money—or running out of space.

Understanding Liter Capacity

One liter equals roughly the volume of a standard water bottle. So a 20-liter waterproof bag can hold about 20 water bottles‘ worth of gear. But that abstract measurement becomes much more useful when translated into actual camping items.

Size Guide by Activity

Day Trip (5–10 liters)

A 5- to 10-liter waterproof bag fits inside your daypack or clips to the outside. What fits? A spare shirt, socks, rain jacket, snacks, power bank, and small first aid kit.

Typical weight: 50–150g | Best for: Summit pushes, day hikes, organization pouch

Overnight or Weekend (10–20 liters)

The 20-liter size is one of the most popular choices on the market. It holds enough for a full change of clothes, a towel, toiletries, and some electronics. A 20L dry bag can also serve as a rucksack liner or contain a sleeping bag for wild camping-6.

Typical weight: 150–300g | Best for: Weekend trips, car camping, primary carry bag

Multi-Day Backpacking (20–40 liters)

For multi-day trips, the 30- to 40-liter range is common for holding your core camping essentials. However, many experienced backpackers prefer using multiple smaller bags rather than one giant sack—for example, a 20L bag for clothing, a 13L for food, and an 8L for electronics. This color-coded system makes it easy to grab exactly what you need without emptying your entire pack. When buying a set, look for different color bags to help you identify contents at a glance-6.

*Typical weight: 200–500g | Best for: Thru-hiking, extended backpacking, organized packing*

Extended Expeditions (50+ liters)

Once you cross the 50-liter threshold, you are entering expedition territory. These bags are designed for long-distance kayak camping, family camping, extended rafting trips, or basecamp-style adventures where you need to haul bulky gear. The YETI Panga 100L, for example, protects sleeping bags, camp equipment, and clothes even in torrential terrain–.

Typical weight: 500–1500g | Best for: Family camping, group trips, whitewater expeditions

Visual Size Reference Chart

One Large Bag vs. Several Small Ones?

For most campers, several small bags are better than one large bag. Here‘s why:

• Organization: Keeping gear separated by category means you never have to empty everything to find one item.

• Flexibility: On a day hike, leave the large bags at camp and take just the 5L or 10L bag.

• Redundancy: If one bag fails, your other gear remains protected.

• Air management: Compression dry bags with purge valves allow you to push air out while keeping contents dry–.

Common Mistakes to Avoid

• Buying too large: A 40L bag for a day hike adds unnecessary weight and bulk.

• Buying too small: Overpacking strains seams and prevents proper roll-top sealing.

• Neglecting the closure: A bag‘s liter rating assumes you can roll the top down three times. If you overfill it, you cannot seal it correctly.

• Forgetting about inside storage: Remember that these bags are often designed to go inside your main backpack, not necessarily to be carried separately.

Final Tip

When in doubt, size up slightly rather than down. A bag that is a little too large can always be rolled down more to reduce its effective size. A bag that is too small will force you to leave essential gear behind or compromise the waterproof seal. If you are buying for a specific activity—like kayak camping or backpacking—search for bags specifically marketed for that use case, as they often come with additional attachment points and tougher materials.