Why are backpacks measured in liters? (2023)

Why bags are measured in Litres?

Because you simply cannot provide any other unit (quantity to be accurate) to measure the capacity of a backpack other than it's volume. The measurement must be given as the maximum volume it can accommodate! Litre is the unit for volume by the way.

If you're not used to backpacking terminology, the very first thing you'll notice is that bags are often measured in L. The L stands for liters; it denotes how much volume, and not weight, it can hold.

A: The "L" stands for "Liters". So when you see a 25L backpack, that means the capacity of the main pouch is 25 liters.

Yes, 45 liters is more space than most people will need in a day hiking pack. The sweet spot for day packs is more like 15 – 30 liters, which is enough space for a day's worth of food and water, warm layers or rain gear, safety essentials, and other small items.

Medium: 21 to 30 liters

This is the most common size for backpacks. The bags have enough space, but are not larger than necessary. Most school backpacks have several small pockets.

40-50 Liters (The Ultralight Thru-Hiker)

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.

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. Here is a potential packing list for that size depending on where you're headed.

Even if you can't get away with carry-on size luggage, a 50 litre pack is plenty big enough for even the longest trip if you pack well.

The most common hiking backpack size is around 60L (liters). This capacity offers enough space for several days of backpacking yet isn't too large for a single night trip.

Is a 30L backpack too big?

A 30L backpack for travel is usually considered a small to mid-size travel bag. In general, you can expect to fit up to a week's worth of items inside a 30 liter backpack. Note that travel backpacks and bags can go up to 45, 50 or even 70 liters!

Bags larger than 45L cannot be carried on. If you see a 50L backpack marketed as a carry on, double-check the dimensions. It's probably too big to technically qualify as a carry on. Most airlines won't measure your bag or look too closely at it if it's close to the limits.

Is 65 liters big enough for backpacking? For most people and most hiking routes, yes, a 65 liter pack is big enough for backpacking. It's perfect for a long weekend even if your gear list isn't exactly lightweight. With a thoughtful lightweight backpacking setup it's big enough for a week without resupply.

A weekend backpack like a standard 40L backpack is big enough to carry a backpacking sleeping bag, small tent, and pad, as well as extra clothing and layers. Other things you'll need to carry include a small stove, food and basic cookware, plus a water filter/purifier, first aid kit, and navigation tools.

For example, American Airlines requires that the sum of three sides does not exceed 36 inches (92cm), and Northwest Airlines requires that it does not exceed 15 inches × 11 inches × 6 inches ( 38 cm×28 cm×15 cm). Therefore, if you bring a 60L backpack, don't pack it too full.

Most airlines allow carry-on luggage that measures up to a maximum of 22 x 14 x 9 inches. In terms of volume, backpacks that are 40-45 liters are good as a carry-on. Anything bigger than that might require you to have it checked in instead.

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.)

The capacity of a backpack measured in liters will be roughly equivalent to twice the number of soda bottles you can dump into it. For example, a 50L backpack will theoretically be able to hold about 25 bottles of soda, which is much easier to visualize.

The standard everyday backpack typically measures 22 × 14 × 9 inches (55.9 × 35.6 × 22.9 centimeters), give or take a few inches. They are designed to carry around 15 to 35 liters (4 to 9.2 gallons) of supplies at a time.

Backpack sizes are measured in two ways: the first is by measuring the volume of the bag, which tells you how much it can hold. The volume of a backpack is measured using cubic inches or liters. The second way to measure a backpack size is through the specific dimensions of the bag (length, width, height, or depth).

How do I calculate backpack Litres?

Most long term travellers require a larger bag than this. Some backpackers will use a 25-30-litre bag as a daypack because it's big enough to carry everything you'll need for a day out. Be aware though, unless you pick up a collapsible 25-30-litre bag, it can be difficult to carry along with your main bag.

A 30 litre backpack, is also suitable for weekend trips as they will easily accommodate spare clothing, water, food and other essentials. However, if you have to take sleeping bags and other camping gear, it's likely you'll need a larger rucksack.

This backpack volume is large enough to hold a sleeping bag, a one or two-person tent (or a hammock sleep system), extra clothes, a backpacking stove, water filtration gear, a hydration system or water bottles, and all the other personal items and nic-nacs that backpackers commonly carry.

However, you can generally bring a backpack that's up to 22 x 14 x 9 in (56 x 35 x 22 cm) in size as a carry on bag with most US-based airlines. Additionally, most airlines allow a personal item that's up to 18 x 14 x 8 in (46 x 36 x 20 cm) in size, which is good enough for some small backpacks.

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.

Large Backpacks: 40+ Liters

Large backpacks have a capacity of 40 liters or more, which is plenty of space for all your travel gear, even on longer journeys. If you're planning a backpacking trip for seven to ten days (or longer if you're travel-savvy and can pack light), this is the size you'll want.

CAMPING ESSENTIAL GEAR - With 50 liter large capacity but only 2.1 pounds weight, it's enough for 3-5 days travel or outdoor adventure. Fits women and men and meets size requirements for most airlines.

21–35 liters: This is the sweet spot for most hiking and travel daypacks. There's enough capacity to hold food, clothing and some extras, like a camera and a book. 36–50 liters: These larger packs are ideal for trips that require additional clothing and gear, such as climbing, mountaineering or non-summer hiking.

If you want to embark on a multi-day journey where you'll be carrying kit like shelter, sleeping gear, clothing for different conditions and all your food, a 50L + bag is probably the best backpack for you.

Can you carry-on a 70l backpack?

Yes, you can.

However, most airlines have between 25 and 50-pound weight restrictions. Yet, some budget airlines have an even lower weight limit. The real trick is to measure and weigh the backpack at home before setting foot in the airport.

Carry-on items stored overhead must be 24 by 16 by 10 inches. Personal items for under the seat – including purses, briefcases, cameras, food containers, laptops and backpacks – cannot be larger than 16 1/4 by 13 1/2 by 8 inches.

It has one main zipped compartment with an inner mesh pocket and the different styles of handles make it perfect for multiple uses as a sports bag or travel bag. Dimensions 60x30x35cm.

Although the dimensions may vary, in general, the space under an airplane seat can accommodate backpacks 18 inches long, 14 inches wide, and 8 inches high. For example, here are the maximum personal item sizes for a few of the biggest airlines in the USA (as of May 2022):

Size of Backpack Based on Trip Length

The standard carry-on size is 56 x 45 x 25cm, but this varies between airline so double check before packing. I've never had a problem using my Fjallraven Kanken (16L) or Fjallraven Bergen (30L) as carry-on luggage.

The short answer: Yes, a backpack is generally considered a personal item if it fits under the seat in front of you.

Carry-on bags shouldn't be larger than 22 inches long, 14 inches wide and 9 inches high including handles and wheels. Dimensions of personal items should not exceed 18 inches long, 14 inches wide and 8 inches high. There are no weight restrictions for carry-on luggage.

For travel with your backpack as hand luggage, a 20-30 litre bag will be plenty, but for more long-term travel you'll need something between 35-45 litres.

The first thing you need to do is multiply the length by the width by the height. That gives the number of cubic millimetres. To calculate the number of litres, you then divide that number by a million.

If you are trying to measure the volume of a bag at home, the simplest way to do it is to multiply out the dimensions that you gathered in the “Measuring Dimensions” section above and then multiply the length by the width by the height of the bag to get a rough estimate of its volume.

How do you calculate bag size?

1. Width (W) of the bag = width + depth of the container + 2" for a looser fit. 2. Length (L) of the bag = height of the container + half of the depth to the height.

That standard unit of measuring liquid is called a liter. Liquids such as water, milk, petrol, and oil are measured in liters, milliliters, centiliters, kiloliters, etc.

Backpack sizes are measured in two ways: the first is by measuring the volume of the bag, which tells you how much it can hold. The volume of a backpack is measured using cubic inches or liters. The second way to measure a backpack size is through the specific dimensions of the bag (length, width, height, or depth).

10 Litre bag: 55 cm long x 30 cm wide (21.75 inches x 11.75 inches) when laid flat. 20 Litre bag: 70 cm long x 36 cm wide (27.25 inches x 14.25 inches) when laid flat. The diameter of the Dry Bag when full is 7 inches. The height when folded down 3 times is 16.5 inches.

LARGE FOLDABLE DUFFLE: It extends to 28.3 x 16.5 x 12.9 inch with 85 Liters capacity and 2.03 pounds.

The suitcases have capacities of about 25 to 50 liters, which equals about 10kg of luggage.

This backpack volume is large enough to hold a sleeping bag, a one or two-person tent (or a hammock sleep system), extra clothes, a backpacking stove, water filtration gear, a hydration system or water bottles, and all the other personal items and nic-nacs that backpackers commonly carry.

"Linear inches" simply means the sum total of your bag's length, width and height. So if your airline allows carry-on bags that measure up to 45 linear inches, and your bag measures 20 inches by 10 inches by 9 inches, its measurement in linear inches is 20 + 10 + 9 = 39 inches, so it would be allowed.

Choosing the Right Size Checked Bags

Medium-sized check-in luggage measures 25-26” tall and around 18” wide.

How many Litres is my garbage can?

A standard kitchen trash can is normally about 13 gallons and holds about 50 liters of trash. A standard size kitchen garbage bag should fit fine in these and you can even purchase ones that are scented and of different thickness.

A jug of milk holds about the same amount of liquid as a bottle of soda. This means its volume would be best measured in liters.

Makes up 1000 millilitres i.e.: 1 litre = 1,000 millilitres.

litre (l), also spelled liter, unit of volume in the metric system, equal to one cubic decimetre (0.001 cubic metre). From 1901 to 1964 the litre was defined as the volume of one kilogram of pure water at 4 °C (39.2 °F) and standard atmospheric pressure; in 1964 the original, present value was reinstated.