What size crossbody bag do you need?

When choosing a crossbody bag, it’s easy to focus on colour, shape and style while overlooking one of the most important questions like what size do you actually need?

The best size depends on what you carry, where you’re going and how you use your bag. A bag for your phone, keys and cards needs considerably less space than one for a day of sightseeing, hiking or an overnight trip.

Bigger isn't always better, either. Choosing a bag that matches what you actually carry can help you stay organised, avoid unnecessary weight and keep everything you need within easy reach.

Choosing the best fit comes down to matching the crossbody bag's capacity with the activities you have planned.

From compact phone bags and minimalist slings to larger crossbody bags for travel, this guide will help you understand the different sizes available and find the right bag for your lifestyle.

What is a good size for a crossbody bag?

There is no single “right” size for a crossbody bag, the best size is the one that comfortably holds what you need for the activity you're doing.

Crossbody bags come in very different shapes and capacities. Even two bags described as “small” can have quite different amounts of usable space depending on their dimensions, compartments and how they sit on the body.

When choosing your size, think about:

• Daily essentials: phone, keys, cardholder, sunglasses and lip balm

• Travel: passport, phone, wallet, water bottle, charger and travel essentials

• Events and festivals: phone, cards, keys, sunglasses and portable charger

• Commuting: everyday essentials plus a notebook, tablet, water bottle or other work items

• Dog walking: phone, keys, treats, waste bags, water and personal essentials

• Hiking: water, snacks, extra layers and equipment 

At The Healthy Back Bag, choose from three sizes: Small for your phone, keys and cards, Medium for everyday essentials, and the 20 litre Big Bag for travel, overnight stays and bigger loads. All three share an ergonomic shape that sits close to the body and spreads weight evenly. 

Nomii takes a more minimalist approach, with the Pocket, Baglett and Sling: compact designs for grab and go days when you only need the essentials. 

What are the different sizes of crossbody bags?

The best crossbody bag size depends on how much you need to carry, from a few everyday essentials to everything you need for a weekend away.

At The Healthy Back Bag, our range goes from the Nomii Pocket for the absolute essentials through to the 20 litre Big Bag for travel and longer days out. Each size is designed around a different amount of carry, so rather than choosing the biggest bag available, start by thinking about what you actually need to take with you.

All bags have an adjustable strap, so you can change where the bag sits depending on how you are wearing it and what you are doing.

The capacities above are a guide rather than an indication of exactly how many items you can pack. The shape and construction of a Healthy Back Bag are designed to work with the body, so overfilling a bag with large, rigid items can affect how well it sits and functions.

Phone bags and minimal carry bags

If you're only taking your phone, cards and keys, you don't need a large crossbody bag.

The Nomii Pocket is the smallest option in the range, measuring 19 × 13 × 3cm making it the perfect phone bag. It's designed specifically for the essentials so it’s a natural choice when you want to keep your carry to a minimum.

Think:

• Phone

• Cardholder

• Keys

• Lip balm

It's particularly useful for concerts, evenings out, festivals or quick trips when you don't want to carry a full-sized bag.

The Mini Baglett gives you a little more room, with a 1 litre capacity and dimensions of 20.5 × 11.5 × 9cm. It is designed for minimal essentials and can be worn crossbody or around the waist.

A good rule of thumb: if your packing list starts and ends with phone + keys + cards, stay small.

Small crossbody bags

Baglett and Sling

For a little more than the basics, the Baglett and Sling give you useful extra capacity without moving into a laSmall crossbody bagsrger everyday bag.

The Baglett has a 1.5 litre capacity and measures 25 × 14 × 11cm. It has enough space for your phone, keys, glasses and headphones, with room for a few other small essentials.

Example Baglett packing:

• Phone

• Cardholder

• Keys

• Sunglasses

• Headphones

• Lip balm

It's a useful size for running errands, meeting a friend for coffee or taking your essentials on a dog walk.

If you need to carry a little more, the 3.5 litre Sling measures 29 × 17 × 12cm. It is designed to carry your everyday essentials plus a 500ml water bottle or mini umbrella.

Example Sling packing:

• Phone

• Cardholder

• Keys

• Sunglasses

• Headphones

• Power bank

• 500ml water bottle or compact umbrella

That extra capacity makes the Sling particularly useful for busy days in town, dog walks, travelling or weekends exploring.

Healthy Back Bag size Small

If you want one versatile everyday bag with room for more than the essentials, the 6 litre Small is the next step up.

At 43 × 23 × 15cm, the Small is the most popular everyday size in the Healthy Back Bag range. It has a 6 litre capacity and is designed to carry your everyday essentials with room for larger items such as a drink bottle, Kindle or tablet.

Its unique teardrop shape also makes it a comfortable and ergonomic choice. 

Example Small packing:

• Phone

• Wallet

• Keys

• Sunglasses

• Water bottle

• Kindle or tablet

• Charger

• Small umbrella

• Light layer

This is the size to consider if a Baglett or Sling feels too restrictive, but you don't regularly need the capacity of a Medium.

Medium and large crossbody bags

Choose the Medium when you regularly carry a well-stocked bag or need additional space for longer days out.

The Medium measures 49 × 28 × 18cm and has a 9 litre capacity. It's designed for people who typically carry more, as well as for day trips and sightseeing. It can accommodate your everyday essentials alongside an iPad or tablet.

Example Medium packing:

• Phone

• Wallet

• Keys

• Sunglasses

• Water bottle

• iPad or tablet

• Charger

• Notebook

• Snacks

• Light layer

This makes the Medium a useful middle ground: more capacity than the Small, without moving all the way up to the Big Bag.

When carrying more, remember that capacity isn't the only consideration. How you organise the contents and distribute heavier items can affect how the bag feels when worn.

The Healthy Back Bag's ergonomic shape and internal organisation are designed to help the bag work with your natural balance. 

The Big Bag

The 20 litre Big Bag is the largest size in the range and is designed for days when you genuinely need to carry more.

At 54 × 33 × 21cm, the Big Bag has a 20 litre capacity. It's roomy enough to work as an overnight bag, carry-on bag, beach bag, gym bag or for longer day trips and expeditions.

Rather than thinking of it simply as a “bigger handbag”, think about the Big Bag as a large crossbody or backpack alternative designed for a bigger day or a short trip.

Example Big Bag packing for an overnight trip:

• Phone

• Wallet

• Keys

• Travel documents

• Water bottle

• Toiletries

• Spare top

• Underwear

• Lightweight waterproof

• Charger

• Book or tablet

For a hiking or active day, the capacity could instead be used for:

• Water

• Food and snacks

• Extra layer

• Waterproof jacket

• Sun protection

• First-aid essentials

• Phone and other personal items

The Big Bag is also designed with multiple pockets and compartments, helping you organise a larger load while keeping frequently used items accessible.

Remember: bigger doesn't always mean better. If you only need your phone, keys, wallet and sunglasses, a 1.5L Baglett or 3.5L Sling is likely to be a more appropriate starting point. If you're carrying clothes, toiletries, travel essentials or a laptop, the 20L Big Bag gives you the capacity to do more with one bag.

Which crossbody bag size is best for your lifestyle?

The right size depends on the activity, not just the amount of space available.

Start with what you need to carry, then consider how long you'll be carrying it and where you'll be using it.

Crossbody bags for everyday

For everyday use, the Baglett, Sling and The HBB Small cover three different levels of capacity.

If your day involves little more than your phone, keys, cards, glasses and headphones, the Baglett may be enough.

If you want to add a water bottle or mini umbrella, the Sling gives you that extra flexibility.

For a fuller everyday load, the HBB Small gives you space for a drink bottle, Kindle or tablet as well as your usual essentials. It also provides that additional comfort with its ergonomic teardrop design. 

A simple way to think about it:

Baglett: Just the essentials.
Sling: Essentials + water and a little extra.
HBB Small: Everything I need for the day.

If you're deciding what to carry the essentials or trying to pack light, starting with your usual everyday items can help you work out which capacity you actually need.

Sizing up a crossbody bag for travel

For a travel bag, choose your crossbody size based on what you need to have with you during the journey or day, rather than everything you're taking on the trip.

When using a bag while travelling, smaller crossbody bags can be useful for keeping your most important belongings accessible, while a larger one can take on more of your overall luggage.

Travelling light

A Sling or Small can be useful for sightseeing, city breaks and days when you want to carry your essentials plus water and a few additional items.

Sling example:

Phone + passport + cards + keys + sunglasses + 500ml water bottle

Small example:

Everything above + Kindle/tablet + powerbank + light layer + compact umbrella

Carry-on travel

The Big Bag is the largest HBB option, with a 20 litre capacity for substantially more travel essentials.

It can work as an overnight bag or carry-on, with space for clothing, toiletries and other larger items.

The important thing is to remember that carrying more also means carrying more weight. A larger capacity doesn't mean it needs to be filled.

For more options, explore our crossbody travel bags.

Wearing the right sized bag for festivals and events

For festivals and events, choose the smallest bag that fits what you need and meets the venue's bag restrictions.

For a minimalist festival day, the Nomii Pocket, Mini Baglett or Baglett could be enough for:

Phone + cards + keys + sunglasses + lip balm

If you want to take water, the 3.5-litre Sling gives you space for a 500ml bottle alongside your daily essentials.

Always check the individual venue's rules before you go. Arena and concert venues can have specific size requirements, including A5 or A4 restrictions.

For a long day in a crowded environment, a compact, well-organised crossbody or sling can also make it easier to keep your festival bag essentials close and accessible.

A secure festival bag can be particularly useful when you're moving between crowds, queues and performances.

Using a crossbody bag for dog walks

For a short dog walk, a Baglett or Sling can give you enough room for the essentials while keeping your hands free.

A typical dog-walking load could include:

• Phone

• Keys

• Treats 

• Poo Bags 

• Cardholder 

• Sunglasses 

• Ball 

• Lead 

• Hair tie 

• Tissues 

• Water 

• Collapsible bowl 

The 1.5-litre Baglett is a good option when you only need the basics, while the 3.5-litre Sling gives you additional room for a 500ml water bottle or small compact umbrella.

For a longer walk, you can move up to the HBB Small or Medium if you need extra water, snacks, layers or other bulkier items. 

The benefit of choosing the right size is that you can also go from walk to coffee without changing bags. Your essentials are already with you, and your hands stay free for the important stuff.

The weather-resistant materials available across the range can also be useful when you're out in changeable weather.

Hands free walking and hiking

For longer walks and hikes, choose a larger capacity according to how much water, food, clothing and equipment you need to carry.

The Sling can accommodate a 500ml water bottle alongside everyday essentials, making it suited to shorter walks.

The HBB Small gives you additional room for things such as snacks, a Kindle/tablet, drink bottle and extra personal items like a small first aid kit.

For longer or more equipment-heavy days, the 20 litre Big Bag provides considerably more capacity for water, food, extra layers, waterproofs and other equipment.

If you're planning a longer walk, our guide to packing a bag for hiking can help you think through how much space you actually need.

For a dedicated crossbody hiking bag, consider the length and conditions of your walk, as well as the equipment you'll need to carry.

The key is to match the capacity to the walk rather than automatically choosing the largest option.

 

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Avoid choosing the wrong sized crossbody bag

The easiest way to avoid choosing the wrong size is to think about what you actually carry before deciding how much capacity you need.

Common mistakes include:

• Buying too large “just in case” – extra space can encourage unnecessary packing.

• Carrying unnecessary items – empty your current bag and look at what you genuinely use.

• Ignoring weight distribution – a full bag can become uncomfortable regardless of its size.

• Choosing style over practicality – consider how the bag works for your everyday routine.

• Not considering intended use – a festival bag and an overnight bag have very different jobs.

• Overpacking travel bags – your crossbody doesn't need to contain everything you own.

A useful starting point is to lay out the things you carry most often, then compare them with the capacity of the bags you're considering.

If you find yourself regularly carrying unnecessary items, our advice on how to pack light can help you reassess what really needs to come with you.

 

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The best sized crossbody bag is one that fits your lifestyle

The best crossbody bag size is the one that gives you enough room for your lifestyle without encouraging you to carry more than you need.

If your everyday essentials fit into 1–1.5 litres, there's no need to jump straight to a 6 litre bag.

If you regularly carry water, a tablet and additional personal items, the 3.5 litre Sling or 6 litre HBB Small may give you a better balance of capacity and convenience.

And if your day involves clothing, toiletries, equipment or overnight essentials, the 9 litre Medium or 20 litre Big Bag gives you the additional capacity you need.

Think about:

• Capacity: how much do you actually carry?

• Organisation: can you easily find what you need?

• Comfort: how will the bag feel once it's full?

• Weight: which items are heaviest?

• Activity: where will you be using it?

• Frequency: is this your everyday bag or an occasional one?

The right size is ultimately the one that works with your routine, your belongings and your plans.

Browse all crossbody bags.

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How big should a crossbody bag be?

A crossbody bag should be large enough to hold everything you need for its intended use, but not so large that you're carrying unnecessary weight and space.

The best way to choose is to start with your packing list rather than the bag itself.

 

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How do I choose the right crossbody bag?

Choose your crossbody bag by matching its capacity to what you carry and how you spend your day.

Ask yourself:

1. What do I carry every day?

2. Do I need to carry water?

3. Do I need space for a tablet or Kindle?

4. Will I need an extra layer?

5. Am I using it for travel, festivals or hiking?

6. How long will I be carrying it?

7. How important is easy organisation?

Then choose the smallest size that comfortably meets those needs.

 

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Which is better, a sling bag or a crossbody?

A sling and a crossbody can both be useful, the better choice depends on how much you carry and how you want to use the bag.

A sling is generally a compact, hands-free option. A crossbody covers a much wider range of capacities. HBB's Small, Medium and Big Bag provide 6, 9 and 20 litres respectively, making them suitable when you need more space.

For minimal carry, Nomii also offers the Pocket and Mini Baglett, giving you even smaller options.

So rather than choosing based purely on the style of bag, think about capacity, activity and how much you need to carry.

 

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Is a crossbody bag better for your back?

A well-designed crossbody bag can distribute its contents differently from a bag that concentrates weight at a single point, but comfort ultimately depends on the bag, how it is packed and how much you carry.

The Healthy Back Bag’s unique shape is designed to contour to the curve of your back minimising the strain on your spine, neck & shoulders. The main zip of the bag sits against your body meaning your belongings are safe and accessible only to you even when wearing the bag. This for example makes it a perfect choice for travel or in crowded areas. 

How you pack the bag also matters. Avoiding unnecessary weight and placing heavier items sensibly can help the bag remain comfortable when worn.

Read more about the design and thinking behind The Healthy Back Bag in How Are We Healthy.

 

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Where should a crossbody bag sit?

How you wear a crossbody bag matters. It can sit across your chest, at your hip or further around your back, depending on the bag, your preferred fit and what you're doing.

The adjustable straps across the HBB range allow you to alter how the bag sits on your body.

For everyday access, you may prefer to position the bag towards the front or side of your body. When walking or moving around, you may prefer it further around your back.

The most important thing is that the bag feels secure, comfortable and easy to access for the activity you're doing.