How to Easily Measure the Volume of Your Backpack in Liters 

 July 29, 2023

By  Keith Terrell

Ever tried squeezing a week's worth of hiking essentials into your backpack, only to find out it's just not large enough? Perhaps you've been racking your brain trying to work out why your friend's backpack looks the same size as yours, but they could mysteriously fit in two extra sweaters and a sleeping bag! The secret lies not in their packing skills, but merely in the volume of their backpack. Think about it like this: Two houses can look similar from the outside, but one might have an attic that dramatically increases its inner space. The same principle applies to backpacks. 

To estimate the volume of your backpack in liters, measure the height, width, and depth of your backpack's main compartment. Then multiply these three values together. Keep in mind that this method gives an approximate result and does not take into account external pockets or material characteristics. Additionally, manufacturers may use different methods to measure the capacity of their bags making comparisons between backpacks difficult.

Understanding how to measure the volume of your backpack in liters will take your packing skills to new heights, and ensure you'll never be caught short of space on your adventures again! So brace yourself as we dive into the world behind the zippers and buckles and rid yourself of unrequired packing stress for good!

Measuring Backpack Volume in Liters

Backpacks have become indispensable for many people, from students to hikers, and even working professionals. Choosing the right size of backpack helps ensure you can carry everything you need without straining your back or shoulders. The universal unit of measurement for backpack volume is the liter (L), but measuring a backpack's volume can be challenging. To determine the appropriate size of your backpack, it is essential to learn how to measure its volume correctly.

Say you want to purchase a new backpack with a specific capacity. You go online and find two different backpacks that both claim to hold 30 liters. However, upon receiving them, one feels significantly bigger than the other. This conundrum is because there is no standardized method for calculating backpack volume across manufacturers. It is also because backpacks come in varying shapes with rounded edges, multiple pockets, and compartments that make measuring their volume complicated.

For a more accurate way of determining a backpack’s capacity, some users use water as a measuring tool. They fill up their closed backpack with water and then pour the liquid into a bucket to gauge the bag’s capacity. However, this will only work if the bag they are measuring does not have any holes or leaks.

Another efficient approach involves measuring the backpack's outer dimensions accurately. Measure each plane of the bag's surface from top to bottom as well as side-to-side while it is empty and on a flat surface. Make sure to measure edge to edge of every individual compartment that makes up the bag.

Some people suggest that using only these linear dimensions alone may include unusable spaces when calculating volume correctly, particularly in smaller bags with curved edges or complex compartments. In contrast, others argue that linear dimensions are still essential for comparing the volumes between different bags and brands.

For instance, measuring a backpack’s volume using a 3D scanner might be more accurate, but scanners are uncommon to come by, especially for everyday users. Therefore, it is necessary to rely on easy and accessible methods like measuring the length, width, and height of the backpack.

In the following section let's explore the tools needed in the process of measuring backpack volumes accurately.

Process and Required Tools

To measure the size or capacity of your backpack, you will need three things:

  1. A tape measure
  2. A level surface
  3. A calculator or smartphone with an app with the ability to calculate cubic meters.

To start measuring your bag, place it on a flat surface or table that is parallel to the ground. Make sure to leave all zippers open and close any external pockets on the bag. This allows you to get an accurate measurement of just the main storage compartment of your backpack.

Suppose you own an internal-frame hiking backpack with several compartments and nooks that would make getting precise measurements challenging. In this case, you can dismantle it into its components: main compartment, sleeping bag compartment, and other tiny compartments such as hip belt pouches and mesh pockets. Measuring each of these parts separately will give you a better idea of how much your backpack can hold.

Regardless of whether some companies fill bags with pellets or use small measuring tools to calculate usable space when determining their bags sizes; however here we recommend our readers our method as simple and easy.

Next, it is time to take measurements of each dimension:

  • Length: Measure from top to bottom along one vertical side of the backpack
  • Width: Measure across from one side seam to another
  • Height: Measure from front to back to gauge overall depth

Combine these three dimensions by multiplying them together - Length x Width x Height = Total Volume. However, in some cases, due to curved edges or oddly shaped compartments, the result might not be accurate.

Think of it as being a cake recipe where you have butter squared-off before adding it to the mix or imagine how looking at every piece of a flattened paper bag makes it easy to calculate its surface using multiplication. In the same way, linear dimensions are simply individual metrics that need to be multiplied together to calculate an object's overall volume.

Having laid out the process and required tools for measuring backpack volumes, we’ll now delve into converting cubic measurements to liters.

Key Takeaway

Measuring the size or capacity of a backpack is easy when you have the right tools and know-how. To accurately measure your backpack, you will need a tape measure, a level surface, and a calculator or smartphone with an app that can calculate cubic meters. It's important to place the backpack on a flat surface, leave all zippers open, and close external pockets before measuring.

If the backpack has multiple compartments, it's best to measure each one separately for better accuracy. Once you have the dimensions, simply multiply them together to calculate the total volume of the backpack in cubic meters. Finally, converting cubic measurements to liters will make it easier to compare sizes across different backpacks or brands.

Converting Cubic Measurements to Liters

Measuring the volume of a backpack in liters is not only more accurate but also an international standard. In order to do so, we need to convert cubic measurements into liters using the correct formula. While this process is generally straightforward, there are some nuances.

Let's say you have a backpack with dimensions of 40cm x 30cm x 20cm. To find the volume in cubic centimeters, you would multiply these values:

40cm x 30cm x 20cm = 24,000cm³

To convert cubic centimeters to liters, divide by 1000:

24,000 ÷ 1000 = 24L

So, your backpack has a volume of 24 liters.

It's important to note that while this formula works well for rectangular shapes, other shapes might require a different approach.

Let's delve into the specifics of this conversion formula and examine some further examples.

The conversion from cubic meters to liters is simple - one cubic meter is equal to 1,000 liters. For example, if you have a backpack with dimensions of 0.5m x 0.3m x 0.2m (which equals a total volume of 0.03 cu m), you can calculate the capacity in liters as follows:

Total volume (in cu m) x 1000 = Capacity (in liters)

0.03 x 1000 = 30 L

Here's another example: let's say you're measuring the interior space of a round backpack with a diameter of 45cm and a depth of 35cm. You first need to calculate the volume by using this formula:

Volume = πr²h

where r is half the diameter and h is the height/depth

π(45/2)² x 35 = 63,615cc

To convert cubic centimeters to liters, divide by 1000:

63,615 ÷ 1000 = 63.6 L

However, it's important to keep in mind that when using the standard volume formula (length x width x height), the resulting volume may not always be accurate since backpacks often have rounded edges. This may result in a higher capacity measurement than can be expected from the actual space available within the backpack.

To address this issue and ensure accuracy in measuring backpack volumes, manufacturers use different methods and techniques.

Conversion Formula and Illustrative Examples

As previously discussed, calculating backpack volume in liters is done by converting cubic measurements into liters. The conversion is simple - just divide the total volume (cubic meters or cubic centimeters) by 1000 to get the capacity in liters.

Let's take an example of a backpack with dimensions of 65cm x 40cm x 25cm (which equals a total volume of 65,000 cc). We'll use the same formula as before:

Total volume (in cc) ÷ 1000 = Capacity (in liters)

65,000 ÷ 1000 = 65 L

Another example is a small shoulder bag with dimensions of 20cm x 15cm x 10cm (which equals a total volume of 3000cc). We again use the same formula:

Total volume (in cc) ÷ 1000 = Capacity (in liters)

3000 ÷ 1000 = 3 L

There are also some online calculators that can help you convert cubic measurements to liters, especially for non-rectangular shapes.

Think about it like this – if you have a container filled with water, its total volume would be measured in liters. But if you want to know the capacity of the container, you would measure it in terms of how many liters it can hold. Similarly, backpack volume is measured in liters because its capacity is determined through that measurement.

However, it's important to remember that despite this simple formula and easy conversion process, there are other factors to consider when choosing the right backpack for your needs.

Firstly, as we discussed in the previous section about adjusting measurements for unusual backpack shapes, non-rectangular or unconventional backpack designs will require different methods for measuring volume. Additionally, external pockets and material characteristics might impact the actual space available within a bag.

Moreover, manufacturers use different techniques to measure their bags' volume such as filling them with small pellets or only measuring compartments with zippers. This makes comparisons between backpacks difficult and highlights the importance of considering practical uses as a key factor when choosing the right backpack.

Choosing a backpack solely based on its volume would be like choosing a water bottle only by the amount of water it can hold – it wouldn't necessarily indicate whether it's practical or suitable for your specific needs.

With these points in mind, understanding how to measure backpack volume in liters remains an essential component when selecting a new backpack.

Common Backpack Capacities and What They Mean

Backpacks are an essential item for anyone on the go, whether it is for school, work, or outdoor activities. However, selecting the right backpack with the right capacity can be overwhelming. The volume of a backpack is generally measured in liters and ranges between 15 liters to over 60 liters. It's important to understand what these capacities mean before selecting a backpack that suits your needs.

Small backpacks usually have a capacity of less than 20 liters and are ideal for everyday use. They offer enough space to carry your essentials such as your wallet, phone, snacks, and a water bottle. Small backpacks are perfect for short commutes to work or school or running errands around town.

Medium-sized backpacks typically have a capacity ranging from 25-30 liters. They are suitable for activities such as day hikes or overnight trips where you need to pack a little more than just your daily essentials. A medium-sized backpack can hold extra layers of clothing, food, water bottles, and other gear needed for outdoor activities.

For longer excursions or camping trips lasting multiple days, large backpacks with a capacity of 35 liters or more are necessary. These types of backpacks accommodate all the supplies required for several days' outings into nature. Large backpacks are also designed to carry heavier and bulkier equipment like camping tents, stoves, first-aid kits, and sleeping bags.

Keep in mind that the size of the backpack often correlates with its weight. It is important to steer clear of oversized backpacks that are heavy before being filled with equipment as they can lead to discomfort and injuries. Additionally, ensure that it fits appropriately so that most of the weight rests on the hips rather than shoulders or back muscles.

Different types of professions demand specific types of backpacks. For instance, a photographer may require a camera backpack with specialized compartments and adjustable padding to safeguard and carry their camera lenses safely. These backpacks are typically larger than everyday backpacks and offer an array of compartments.

Backpack capacity is a lot like seat capacity in automobiles. Just as the number of seats determines how many individuals can ride, the volume of a backpack determines how much gear it can hold. Similar to smaller cars having better fuel economy and being cheaper to own, smaller backpacks are easier to carry, less bulky, and come at a lower price point.

Understanding what different capacities mean will assist you in selecting the correct backpack size for your needs. However, selecting the right volume is only one piece in finding the perfect backpack. It's critical to consider other factors when choosing the right backpack; such as weight distribution, structure and fit adjustment mechanisms, ventilation systems, and more.

Backpack Sizes and Their Practical Uses

Now that we have understood the capacities associated with different types of backpacks, let's delve deeper into the practical uses of different backpack sizes. Your selection will depend on what exactly you need to pack and where you plan on taking it.

Small daypacks or knapsacks are ideal for short walks or commuting on city streets during rush hour jams. They're designed to keep essential items close by such as keys, wallets, phones, lunchboxes, umbrellas, etc., handy frequently without needing to take them off. Daypacks usually have limited carrying capacity making them suitable for daily use only.

Mid-range versatile packs often range from 20-30 liters, which give additional room for personal items or gear while staying small enough for daily use. Designed for extended trips away from home such as day hikes or even overnight camping trips into nature reserves or municipal parks, these backpacks can carry all the necessary equipment to get you through your hikes confidently.

Large and expedition-sized backpacks generally have a capacity of 35 liters or more, with some bags going over 100 liters. These packs are designed for extended trips or expeditions where you need to carry hefty supplies like camping gear, clothes, food, water supplies, tools, etc. Their larger volumes and higher weight-carrying capacities make them ideal for hikers staying on remote campsites.

It's important not to get fooled by the size of a backpack as it doesn’t determine its practical use. Depending on the structure, pockets design and additional functionalities attached to the bag could boost their versatility irrespective of their size. So before selecting your backpack, ensure that fit your requirements precisely rather than rely on only size.

Backpack sizes and capacities vary greatly depending upon your specific needs. Make sure to consider what you plan on carrying in your backpack now and in the future when making your selection. Few factors to keep in mind include durability, adjustability, comfort levels while carrying heavy loads, and extra compartments for organizing your essentials much more efficiently.

Adjusting Measurements for Unusual Backpack Shapes

Not all backpacks are created equally, and some may have unusual shapes that make measuring their volume using conventional methods challenging. For instance, backpacks with rounded edges or those made from flexible fabric can be tough to measure accurately.

One technique that you can use is to stuff the backpack with packing paper or tissue until it is full, then pour out the contents into a large bin or container with marked measurements. Take note of the volume of the displacement and subtract this amount from the total volume of the container to get an accurate measurement of your backpack's capacity.

Another method is to divide your backpack into smaller sections and measure each separately before adding them up. This works especially well for backpacks with multiple compartments and pockets. Be sure to factor in any space lost due to overlaps between the different sections.

Measuring backpack capacities with unusual shapes is like solving a puzzle. It requires patience, creativity, and resourcefulness to come up with the best solution.

While it may be tempting just to eyeball the approximate volume of your backpack, using one of these techniques ensures a more precise result. Remember that inaccuracies in measurement can lead to overpacking or underpacking, which can affect your overall comfort and safety during long hikes or trips.

Now that we've discussed how to adjust measurements for unusual shapes let's move on to techniques for accounting for pockets and rounded edges.

Techniques to Account for Pockets and Rounded Edges

Backpacks usually have pockets and compartments that add complexity when determining capacity. The most common problem is calculating space lost due to rounded corners and edges. Since they don't follow straight lines, these areas result in dead space that's not usable for storage.

One method is called "water displacement." First, fill a bathtub partially with water then submerge your backpack. Press it down until it is entirely underwater and all pockets are full. Wait for the air bubbles to escape before removing the backpack from the water. Measure the amount of displaced water in liters, which is equivalent to the volume of the backpack. Be sure to subtract any space taken up by items in pockets.

Another technique uses a garbage bag. Place your empty backpack inside a large trash bag that reaches up to the top of its straps. Sealing off the bag as tightly as possible, use a vacuum cleaner to suck out all air from within and collapse the bag around the pack. This method can help determine how much extra space you might have within your backpack by measuring any excess material and comparing it to manufacturer estimates.

For those who want a quick-and-easy solution for measuring their backpack volume's external pockets, consider stuffing them with materials like foam blocks before measurement. This works best when you don't have specific shapes or sizes of items to fit into your compartments.

Keep in mind that not all manufacturers calculate backpack capacity using the same method, so it's vital to compare apples-to-apples when comparing different models. While some may take only main compartments into account, others may include every pocket and pouch available. Additionally, depending on where you measure, some brands may report different values than those provided by calculating total volume using traditional formulas.

Whatever method you choose, double-checking your measurements will help ensure that your backpack comfortably fits everything you need without weighing you down significantly. Remember that understanding how to measure backpack capacity can save time and hassle down the line when packing for extended trips or hikes.

By following these techniques for measuring unusual-shaped backpacks and accounting for dead spaces due to rounded edges or pockets, you will be able to get accurate measurements regardless of how complicated or unfamiliar your carrying gear’s shape is.

About the author

Keith is a one bag traveler and the owner of Backpacks Global. His go to backpack is the Osprey FarPoint 40.

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