How Many Liters For Ultralight Backpack?

How Many Liters For Ultralight Backpack? A pack this size can be used for multi-day backpacking trips and even Continental Trail thru-hikes provided you keep a lightweight and minimalist philosophy. How many liters should backpack be? Size Capacity Suggested Uses Mini and Small Backpacks6 -10 Litres Days Out / Kids Bags / Sports Daypacks 10