A liter is roughly 60 cubic inches (61.02 but why quibble?). So, a 30 liter backpack has a capacity of 1800 cu in (30 x 60) or about 1 cubic foot. You can put 1 pound of stuff in there or a100 lbs, but the limitation is that it would have to fit in a 1 cubic foot container.
MEDIUM BACKPACKS (20 – 35L)This capacity range is considered a medium-size backpack and is probably the most popular bag capacity out there. It's great for taking to school or work, depending on the styling, and can also be a great travel pack for taking on a plane.
Backpacks are measured by the total capacity of all of the pockets in litres. Essentially, you'll be able to fit 30 litres of gear in a 30 litre backpack. This however might not mean a great deal when you are trying to decide if a backpack is big or small enough for your needs.
A 30 litre backpack is plenty, but can be a little bit small for versatility. You need 3 changes of clothes, so that you can wash a new item each day, and have at least 2 days for it to dry.
24-26 liters is considered a medium-size backpack and is probably the most popular bag capacity out there. It's great for taking to school or work, depending on the styling, and can also be a great travel pack for taking on a plane.
24-26 liters is considered a medium-size backpack and is probably the most popular bag capacity out there. It's great for taking to school or work, depending on the styling, and can also be a great travel pack for taking on a plane.
10 to 19 liters: For light loads and 13-inch laptops. 20 to 29 liters: Best for students and 15- to 16-inch laptops. 30 to 39 liters: For super-size workloads and weekend trips. 50 to 80 liters: For hikers and campers.
Is 30-inch luggage too big to use as a carry-on? In all cases, yes. Thirty inches is on the higher end of the different luggage sizes you can purchase. For almost all situations, the absolute maximum luggage size is 21 inches, length-wise.
While personal item size restrictions vary across airlines, most airlines consider a small backpack, purse, briefcase, or laptop bag to be a personal item. These must always fit under the seat in front of you. Many airlines restrict passengers to one personal item and one carry on bag.
Capacity: 35L. This luggage backpack is meet the allowed maximum size of most IATA flights and also fits in the overhead compartment and the underseat in flight. The portable opening facilitates you to quickly pass the airport security check.