What Size Backpack Do I Need for Travel? 20L vs 24L vs 30L vs 40L

Choosing the right backpack size can be surprisingly difficult.

Too small and you're struggling to fit everything you need. Too big and you're carrying around unnecessary weight and bulk.

The right size depends on how you travel, how long you're going for and what you actually need to carry.

So, is 20L enough? Is 24L the sweet spot? When should you move up to 30L or even 40L?

Here's how to work it out.

What Does Backpack Capacity Actually Mean?

Backpack capacity is measured in litres.

A 20L backpack has roughly 20 litres of internal storage space, while a 40L backpack has roughly twice that capacity.

But more litres doesn't automatically mean a better backpack.

A larger bag is useful if you genuinely need the extra space. For everyday use or shorter trips, however, a smaller and more compact backpack can be much easier to live with.

Think of capacity as matching the bag to the journey.

Is a 20L Backpack Enough?

A 20L backpack is generally suited to everyday use, commuting and shorter outings.

It's a good option if you're carrying things such as:

• Laptop
• Charger
• Headphones
• Water bottle
• Small camera
• Notebook
• Light layer
• Everyday essentials

For a day trip, 20L can be more than enough.

For an overnight stay, however, things can start getting tight once you add clothing and toiletries.

Best for: commuting, everyday carry, day trips and light travel.

Is 24L Enough for Travel?

For many people, 24L is a useful middle ground.

It's compact enough to use every day but gives you noticeably more room than a typical commuter backpack.

You can fit your everyday essentials alongside clothing, toiletries and technology for a short trip.

For example, a 24L backpack can comfortably accommodate:

• Several changes of clothing
• Toiletries
• Laptop
• Chargers
• Headphones
• Camera or other small equipment
• Travel essentials

The exact amount depends on what you're taking and how efficiently you pack, but 24L can work particularly well for weekends and short trips.

It's also large enough to be useful for travel without becoming unnecessarily bulky during your everyday commute.

That's why we chose 24L for The Nomad Pack.

We wanted something that could move between everyday life and travel without requiring a different bag for each.

What About a 30L Backpack?

A 30L backpack gives you noticeably more flexibility.

It's useful if you're travelling for longer, packing bulkier clothing or simply prefer having more room.

A 30L backpack can work well for:

• Longer weekend trips
• Cooler climates
• Travelling with more technology
• People who prefer extra space
• Trips where you're carrying more equipment

The trade-off is size.

A 30L backpack can still work perfectly well for everyday use, but you'll generally notice the additional bulk compared with a 20L or 24L bag.

When Do You Need a 40L Backpack?

40L backpacks are getting into traditional travel-backpack territory.

They're useful when you need to carry substantially more equipment or clothing.

For longer trips, backpacking or situations where you're travelling with everything you need for an extended period, the additional capacity can be valuable.

But there's an important downside:

You can only carry so much before the bag starts feeling like luggage.

A 40L backpack can be excellent for the right journey but unnecessarily large for a daily commute or short weekend away.

20L vs 24L vs 30L vs 40L

There isn't one universally correct backpack size.

The best size is the one that matches how you actually travel.

How Long Can You Travel With a 24L Backpack?

This is where packing style becomes important.

A minimalist traveller who packs versatile clothing and avoids unnecessary items might comfortably use a 24L backpack for several days.

Someone who packs multiple shoes, bulky clothing and lots of equipment might struggle to fit everything into the same bag.

The number of days isn't the only factor.

What you're taking matters more than how long you're going.

A summer week away could require less space than a three-day winter trip.

How to Choose the Right Backpack Size

Before buying a backpack, think about your normal use.

Choose around 20L if:

You mainly need a backpack for work, commuting and everyday essentials.

Choose around 24L if:

You want one backpack that can handle everyday life and short trips.

Choose around 30L if:

You regularly travel for longer periods or carry more equipment.

Choose around 40L if:

You're looking for a dedicated travel or backpacking bag with maximum capacity.

Don't Forget Organisation

Capacity isn't everything.

Two backpacks with the same litre capacity can feel completely different to use depending on their design.

A well-organised backpack can make better use of its space than a larger bag with one large compartment.

Look for things like:

• Dedicated laptop storage
• Easily accessible pockets
• Separate compartments
• Practical internal organisation
• Easy-to-use zips
• Comfortable straps

The goal isn't simply to have more space.

It's to make the space you have work better.

Why We Chose 24L

When we designed The Nomad Pack, we weren't trying to create the biggest backpack possible.

We wanted to find the point where everyday carry and travel overlap.

Big enough for a weekend away.

Compact enough for the daily commute.

Organised enough for your technology and essentials.

And simple enough that you don't need to change bags every time your plans change.

That's where 24L made sense.

Because your backpack shouldn't be limited to one type of journey.

It should be ready for whatever comes next.

So, What Backpack Size Should You Choose?

There's no perfect size for everyone.

If you're looking for a compact everyday backpack, 20L may be enough.

If you want more flexibility without moving into a large travel backpack, 24L can be a strong middle ground.

If you regularly need additional clothing or equipment, 30L gives you more breathing room.

And if you're travelling extensively or backpacking, 40L provides considerably more capacity.

The important thing is to choose based on how you actually travel, rather than simply buying the biggest bag you can find.

For us, that balance is 24L.

One bag. Every journey.