What size backpack do I need? Such a tricky question! Right? There is no one to tell you which package will be best for you. Either a big pack? A small one? Medium size? What design? Which color? Etc.

Omg! So many questions, right?

It depends on what purpose you are getting the backpack for, like is it for work or travel, where you are going, how long is the trip, how much Stuff you will carry, and a pack that properly fits you and can handle your body weight.

Here is my article that will provide you with the perfect know what pack and size you should choose.

What quality should your backpack have?

Before purchasing a pack, take knowledge of different backpacks and make a list of them and also make a list of features you need in your pack. Then, make a good investment in your pack because it’s for one time!

With size, other things also matter.

  • Comfortable:-A comfortable pack will last very long because you can wear it with ease every day. The pack with padded straps and back panel does magic, like so much comfort. It will not hurt your back, neck, and shoulders even if you carry a heavyweight.
  • Everyone likes Features:-Multiple features, and why not! It provides ease while traveling. Having a USB charging port, multiple pockets, ventilation channel, pack access, removable day pack, sleeping bag compartment, rain cover, internal frames, hydration reservoir, etc., all make traveling comfortable.
  • The backpack fit: –Measuring your torso length is important. Some backpacks are available in many sizes, and the ranges vary by manufacturer and by gender. Check the product specs tab for size details of a specific pack.
  • Weight: –A perfect lightweight backpack is an ideal backpack. The backpack has its weight, and with that, if we put our Stuff, it becomes heavier, so it better to choose a lightweight backpack.

How are backpacks measured?

Backpacks are measured in cubic inches or liters, but mostly it’s preferred in liters.

Backpacks are divided into three simpler categories: –

  • Extra small packs (0-10 Liters)
  • Small backpacks (11- 19 Liters)
  • Medium size backpacks (20-29 Liters)
  • Large size backpacks (30-39 Liters)
  • Backpacks above 40 Liter are used for traveling and campaign purpose because they are very large and comfortable packs which cannot be used as a daily pack.

Let’s know it in detail

Extra small backpacks: –

These backpacks are usually sling/side packs or a small backpack used to keep your small and essential Stuff.

Sling bags are used in a day trip, shopping, or carried with another main pack to keep extra stuff.

How big is a 6 Liter backpack?

6 Liter backpacks are usually sling/ side bags used for shopping or one-day trips.

You can keep:-

  • Keys
  • Phone
  • Card and cash
  • Sunglasses and the Small Stuff which you will need during the day out.

Best 6 Liter backpacks: –

Arvano Bike Backpack Small Mountain Biking Daypack

How big is a 10 Liter backpack?

you can keep: –

  • Keys
  • Phone, power bank
  • Card, cash
  • Water bottle
  • Snacks
  • Sunglasses and Stuff you want to keep

Best 10 Liter backpacks: –

Quechua Decathlon Kids Adults Outdoor Backpack Daypack Mini Small Bookbags10L

Small size backpacks: –

These backpacks are very small can carry very little Stuff. It can be used as a day pack or for one day trip.

Can carry a limited amount of Stuff inside the backpack. It only has space for a laptop, water bottle, and snacks. These packs are good for a day pack or airline travel.

Backpacks under 19 liters are good for keeping tech stuff like laptops, tablets, etc., and if you want to carry books especially.

It’s a compact size backpack which can fit more of small Stuff than larger ones.

This pack is good for work, school, one-day trips, campaigns. Most people use it as an airport traveling backpack.

These packs are not so comfortable in packing Stuff. It can only fit essentials and is only for people who need simple work backpacks to keep a laptop, water bottle, and some snacks.

You can use these packs to carry extra Stuff while traveling or put only technical Stuff inside it to keep it safe.

You cannot pack large Stuff inside it or plan a night stay trip because it cannot fit a lot of stuff. If you try to fill a lot of Stuff inside it, the pack will feel heavier.

The packs which come under small backpacks: –

How big is a 16 Liter backpack?

Thinking of what you can fit inside it?

Here is a list: –

  • Up to 13″ Laptop
  • Small books
  • Water bottle
  • Headphones, power bank
  • Keys, cards, and cash

A 16-liter backpack is used for work, school, traveling, campaigns, one-day short trips, etc.

Best 16-liter backpacks: –

Herschel Kids’ Heritage Backpack, Black Crosshatch/Polka Dot/Fandango Pink, Youth 16L

Difference between a 16 Liter and 13 Liter backpack

Both the bags can fit the same amount of stuff, but a little different is, a 16-liter pack can fit bigger Stuff than a 13-liter pack.

Laptops less than 14 liters can rarely fit a laptop if it can not more than a 13″ laptop. If you are purchasing a less than 14″ laptop, then search for a big laptop sleeve.

How big is a 19 Liter backpack?

it can fit: –

  • 15″ laptop
  • Water bottle
  • Umbrella
  • Books, folder
  • Headphones, power bank, smartphone
  • Keys, cards, cash, sunglasses, and more of your essential Stuff.

Best 19 Liter Backpacks: –

First Tactical Crosshatch Sling Backpack 19L, Military-Grade, Tactical Shoulder Sling Go Bag for Men and Women

Medium Size Backpacks in detail: –

These are not too big and not too small packs. These are the perfect school and work backpacks that can fit all your essentials.

You can use this pack for keeping big cameras or electronic devices. If you’re a photographer or someone who works and travels with electronic devices, this pack is ideal for carrying all your electric Stuff.

These packs are larger than smaller ones, so they are perfectly padded with that they can fit more of the Stuff.

Let’s know about the sizes.

How big is a 20 Liter backpack?

These backpacks usually have one main compartment and few small compartments for proper organization of Stuff. If want, they are used for work or office purposes and can be good for a one-night trekking trip.

What things it can fit: –

  • 15″ laptop
  • Notebooks and folder
  • Phone, headphones, and power bank
  • Cash, cards, and keys
  • Water bottle
  • One pair of clothes

Best 20 Liter Backpacks: –

Outlander 20L/33L- Most Durable Packable Lightweight Travel Hiking Backpack Daypack (Dark Teal, 20L)

How big is a 25 Liter backpack?

It’s not that big but will be good for work and school.

It’s the perfect size pack for one day hiking and Campaign, but you want to fit some extra stuff, then I recommend you choose another backpack.

What things can go inside it: –

  • Up to 15″ laptop
  • Water bottle
  • Snacks
  • Books
  • Phone, power bank, and camera
  • Keys, card, and cash
  • And some extra stuff according to you also.

I have a comprehensive guide on this particular topic as follows:-

Best 25 Liter Backpacks: –

Herschel Little America Laptop Backpack, Black/Tan Synthetic Leather, Classic 25.0L

Difference between a 20-liter and 25-liter backpack

Difference between a 20-liter and 25-liter backpack

Not at all any major difference but a very minor and invisible one.

How big is a 28 Liter backpack?

What things can you carry?

  • Up to 15″ laptop
  • Books and folder
  • Two pair of clothes
  • Keys, card, and cash
  • Sunglasses
  • Phone and power bank
  • Water bottle
  • Umbrella

Best 28 Liter backpacks: –

Fjällräven Raven 28L Black One Size

Large Size Backpack in detail: –

These are for the overnight trip and weekend vacation backpacks and can fit essentials and your extra Stuff.

These packs will be very large for people who only want to carry essentials in their pack. For example, large packs will be perfect for the gym or work people who want to carry clothes with their daily essentials.

If you are someone shot in height, it will be difficult to find a pack that will fit your size because above 30-liter packs can be quite uncomfortable because the straps don’t fit properly. Likewise, finding a perfect size for short people is challenging, and they might feel the pack a bit heavy.

But you can go with a women’s backpack because those are designed with slim shoulder straps and shorter torsos.

Let’s know thoroughly about the capacity: –

How big is a 30-Liter Backpack?

The perfect size for people who like to keep extra Stuff inside the pack. This pack is best suitable for sports players or the working people who need to keep extra clothes.

You can go on a long or a short trip in a 30-liter backpack; it all depends on how much stuff you are carrying.

What things can fit inside it?

  • Laptop up to 15.”
  • Water bottle
  • Sleeping bag attached to the straps.
  • Umbrella
  • Phone, power bank, headphones, and camera
  • Keys, card, and cash
  • 3-4 pairs of clothes
  • Textbook and folder

I have a comprehensive guide on this particular topic as follows:-

Best 30-Liter Backpacks: –

Herschel Classic Backpack, Black Crosshatch, XL 30.0L

Difference between a 20- and 30-Liter backpack?

The only difference is the size. The larger the backpack, the larger capacity it will have. A person who has good height can carry large size packs, but small people will face difficulty.

Difference between a 20- and 30-Liter backpack?

How big is a 35 Liter backpack?

This pack is best for people who like to keep a lot of Stuff inside their packs, even daily. You can keep whatever Stuff you like from shoes, clothes, and whatnot.

It will be super comfortable for a hiking trip.

What things you can carry: –

  • Laptop up to 15.”
  • Water bottle
  • Headphones, smartphone, camera, and power bank
  • 5-6 pair of clothes
  • Pair of shoes
  • Books and folder
  • First-aid kit if you are going hiking
  • Umbrella
  • Can attach a sleeping bag

An everyday pack can fit best till 39-Liters.

Backpacks over 40 Liter in detail: –

These packs are huge to fit all Stuff for traveling, hiking, campaigns for 5-7 days. However, it will be too large for a daily use backpack.

These packs are very comfortable and have a lot of space to keep Stuff. So you can use it for long trips.

How much Stuff can it fit?

What things it can fit: –

  • Up to 15″ laptop
  • Books and folders
  • 6-7 pair of clothes
  • Two pair of shoes
  • Keys, card, and cash
  • Water bottle
  • Snacks and some food for the trip
  • Headphones, power bank, and phone
  • Sleeping bag

More Stuff according to your need.

Best 40 Liter Backpacks: –

Osprey Farpoint 40 Men’s Travel Backpack

Best 50 Liter Backpack: –

G4Free 50L Hiking Backpack Waterproof Daypack

what size backpack do I need in different places: –

Shopping and one-day trip: –

For shopping and a day trip, you should choose a 6–10-liter backpack. A day trip doesn’t need much stuff to carry so that a small backpack will be perfect.

School and work: –

Going to school and work and carry light Stuff, you can go for a 20-liter backpack. It can fit the exact amount of Stuff you will need. But if you want to carry more Stuff inside your pack like extra clothes for sports or extra files, you should go for a 30–35-liter backpack.

Hiking trip/Campaign: –

For hiking, you need to carry Stuff like a sleeping bag, food items, and many more things, which require space, and if we talk about a perfect hiking pack, then a 30-liter backpack is enough. But if you want to carry extra stuff with you, then a 35–40-liter backpack will be good.

5-7 Days Trip: –

More Stuff, the capacity of the pack will increase. So, for a 5-7 days trip, you can go for a 40-liter pack.

Choose a pack that can fit all your stuff, and don’t overload it because it will put pressure on your shoulders and be uncomfortable.

Choosing the capacity depends on you and how much you pack. For example, you can pack your Stuff in a 30-liter pack for a 5-day trip or in a 40-liter pack; it all depends on how much you pack.

Backpack capacity can vary!

Not all brands have the same measuring scale so, the capacity varies for every brand. There are usually two ways to measure backpack size. One is in cubic and the other in inches. Most inches are preferable, but measurement can vary from brand to brand.

With that, even a 16-liter pack and a 19-liter pack have the same capacity because of the quality of the pack. The material is sometimes thick and can reduce the space to keep things.

It also depends on the pack’s shape, like a U-shaped backpack can fit more things than a drawstring backpack.

So, before choosing a pack, get knowledge about the material quality and shape of the pack and how much it can fit.


Q1) How many liters is a school backpack?

The common size for school backpacks is 21-30 liters. This size pack has enough space and can fit all the stuff properly.

Q2) How big is a standard backpack?

It depends on your height, if your height is 5’5 then every size pack will fit you.

Like a small pack comes in 6-10 liters, a day pack in 10-30 liters, medium size backpack in 30-50 liters and large backpacks are 50 above.

Q3) How many liters backpack for carry on?

A 45-liter backpack is the most efficient use of your carry-on luggage allowance. Backpacks larger than 45-liters cannot be carried on.

Q4) How many liters backpack for travel?

It depends on where you are going, if you are going for a one-day trip a 30-liter backpack is sufficient. 50-liter above backpacks for 4-5 days trip.

Q5) How many liters for backpacking?

If you are going for a long hiking trip with many things then a 50-liter pack will be good. If not then a 30-liter pack will work.


Choosing a perfect pack is a challenging task, but you will get the right one after getting perfect knowledge. What size pack you need depends on how much you carry, so always select for what purpose you are taking a pack and what things you have to carry.

Read the whole article, and you will get detailed knowledge about the sizing of the packs.