With plenty of space to pack bulky clothes, we think the Nomatic Travel Bag 40L would make an excellent carry-on backpack for any and all types of trips since it can be carried multiple different ways—which also makes it an ideal convertible bag.
40 liters is definitely big enough for traveling, as long as you're not an over-packer. It's a good idea not to go for an overly large backpack - overpacking can be as troublesome as under-packing.
Trips of 5 days or more usually call for packs of 70 liters or more. These are also usually the preferred choice for winter treks lasting more than 1 night. (Larger packs can more comfortably accommodate extra clothing, a warmer sleeping bag and a 4-season tent, which typically includes extra poles.)
Backpack size: 18×13.2×11.6; Capacity: 42L. With its large size and multiple pockets, this bag is ideal for storing your clothes, first aid kit, water bottles, food for 3 days and other survival tools.
Admittedly, I have many, many backpacks, and I often get more looking for an ideal backpack for the occasion. I got the XL (30L) version of this backpack.
30-50 liters: In general, luggage that has a capacity of about 50 liters or less is sufficient for a weekend trip. There are lots of carry-on duffels, packs and bags in this size range to choose from.
Though you might find an inch or two of a difference with various airlines, the standard domestic carry-on luggage size is 22 x 14 x 9, which includes the handle and the wheels. This size limit ensures your bag — and ideally everyone else's — will be able to be stored safely in the overhead bin for your flight.
?FLIGHT APPROVED CARRY ON BACKPACK? This 48L luggage backpack is measured as 22 x 14 x 7.5 inches which meets the carry-on baggage allowances for most IATA flights overhead compartment.
A 50L+ backpack is a great friend to those travelling for a few weeks. These bags are spacious and can accommodate a number of outfit changes before you ever have to visit a laundromat. But don't be tempted to fill your pack to its capacity before you've even left - remember to save space for souvenirs!
A 40L backpack sits in the sweet spot between lightweight daysacks and heavy-duty 80L rucksacks. They're extremely flexible – working for average day hikes and overnight wilderness camping. They also give you the extra room needed for climbing gear or winter hikes.
Volume: A 45L backpack is the maximum-sized carry on allowed on most US airlines. For international or budget airlines, choose a bag under 40L. If you want to pack ultralight, anything 35L or under can be carried on virtually any airline. Dimensions: The common 45L volume is usually measured as 22 x 14 x 9 inches.