How Big Should a School Backpack be?

If you’re entering high school or college or a parent of a grade school student or middle schooler, you know that buying school supplies can be overwhelming. If you’re wondering, “how big should a school backpack be?”, wonder no more.

Typically, school backpacks will range from 15 to 40 liters in capacity. The size that each student needs will depend on how many classes they’re taking and the number and size of textbooks, folders, and any other items they need to carry. Also, consider whether you need the backpack to hold a laptop or tablet.

Read on below for a more in-depth discussion of school backpack sizes.

What is The Standard School Bag Size?

Standard School Bag Size

School backpack capacities are generally measured in liters.

Most school backpacks range from 10 to 40 liters. When searching for a bag, search the school supplies or office supplies (or online) according to the age group of the student in question. You should find standard-sized backpacks that typically will meet the needs of that age group.

Here is a video discussion of the various sizes of backpacks and their common uses:

Because most high school and college students bring laptops to class, most school backpacks will be labeled with standard sizes for their laptop compartments. These are typically 13 inches, 15 inches, or 17 inches. Choose the size that most closely matches the laptop you will be carrying.

How Big Should a Grade School Backpack be?

Grade School Backpack

If your child is a kindergartener or in early elementary school, a smaller size backpack of 10 to 20 liters should be adequate. This won’t be too large or too heavy while still offering enough room for folders, small books, and pens or crayons. Some of these smaller backpacks even have different compartments for a small laptop or tablet.

There is a strategy for finding the correct backpack size for small kids. This requires measuring the height of the child’s back and the width of their shoulders.

Child backpack

For the height, measure from the shoulders to the waistline. To find the width, measure between the ridges of the shoulder blades. Add a couple of inches to each measurement for a slightly larger size that will still be comfortable. These measurements should match the measurements of the backpack itself (which should be found on the label).

Here is a handy chart that shows the typical measurements for kids based on age:

measurements for kids

Here is another simple size guide showing the backpack sizes that typically fit students based on their height:

Backpack Sizes

How Big Should a High School Backpack be?

With high school comes more responsibility and, of course, more homework. This means more (and larger) textbooks and more school supplies.

If you can store your books in your locker throughout the day, or if you don’t need to carry many items home, you can probably get by with a backpack of around 20 liters. These are smaller backpacks that are easy to carry while holding the essentials.

For a more medium size, look for a bag of 21 to 30 liters. This is the size most commonly used by high schoolers. This is great for holding more textbooks while not being overly large.

Medium size bag

If you need to carry extremely large, heavy books or other bulky items, you may need a backpack of 31 to 40 liters. A backpack of this size may be overkill if you’re only using it for a day of classes.

As you can see in this photo, a 35-liter backpack is much bulkier than a 13-liter backpack.

large school bag

No matter which size backpack you pick, for the maximum in the organization, look for a backpack that has multiple compartments in addition to the main pocket. This will hold all your school items, plus your phone, car keys, and other supplies you might need throughout the day.

How Many Liters Should a College Backpack be?

Just like with high school backpacks, consider how many large textbooks you need to carry throughout the day. Also, consider your commute to class. Do you live on campus? Are you walking or biking to class? Do you need your bag to hold other gear, like art supplies or science equipment?

Most college backpacks range from 20-30 liters, similar to high school backpacks. Larger backpacks (31 to 40 liters) may be best if you need to carry a ton of supplies and multiple textbooks. Always check to make sure that the bag is comfortable and has enough compartments for organization.

Backpacks range

For a general idea of whether your backpack fits, check to see if it falls below your hips. You want to buy a backpack that fits your torso length, so it should not be too low. If the bag has an adjustable chest strap or waist strap, this can help distribute the backpack’s weight more evenly.

Some students may wish to wheel around a heavy backpack for college instead of carrying it on their shoulders all day. This will be much better for the health of your back.

What Are The Best Backpacks Made of?

Canvas backpacks, typically made out of cotton, are stylish but not as commonly seen today because they tend to be heavier.

Usually, most backpacks will be designed with a synthetic blend of polyester or nylon. These fabrics are durable, resistant to moisture, and dry rather quickly. These will be useful if you happen to encounter a downpour while walking to class. Nylon and polyester are also molds- and mildew-resistant. They also are quite lightweight.

Backpacks made of

For the most durable option, look for ripstop nylon. This is designed with a special type of weave pattern that makes the fabric, as the name implies, very resistant to rips and tears. Backpacks made with ripstop nylon are an excellent choice if you’re looking for a durable, long-lasting day bag that you will also carry to class with you.

Here is a video discussion of ripstop nylon if you’re interested in learning more:

If you’re looking for full waterproofing on your backpack, check out bags that are coated with polyurethane, thermoplastic polyurethane (TPU), or durable water repellent. Of course, while these coatings provide full protection from water, they will make the bag heavier overall.

Another option for a classier look is a leather backpack. These will be resistant to moisture as well. However, leather is much heavier than nylon or polyester. Keep in mind that it is also more expensive.

When evaluating the quality of a backpack, don’t overlook the zippers! Always check to make sure that the entire backpack is easy to zip and that the zipper itself moves smoothly without getting caught on anything. Also, metal zippers will fare much better than plastic over time.

Be cautious of backpacks that close only with a magnetic clasp or snap. These will not provide as much security and may more easily spill.

Finally, consider buying a backpack with padding in the shoulders and across the back for additional comfort.


As we’ve seen, the most common size for school backpacks is 15 to 40 liters. While the smaller sizes are excellent for elementary and grade school, backpacks in the 21 to the 30-liter range are typical for high school and college students. For even more capacity, look for a bag of 31 to 40 liters, but be aware that a bag of this size will be much bulkier.

If you have any other questions about choosing a bag for school, leave a comment below!

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