What Size Hiking Backpack Does a Child Need?

A child does not need the largest backpack they can wear.

They need the smallest backpack that fits properly and holds the few personal items they can carry comfortably.

For many family day hikes, that may mean a compact pack around 10L or 14L. But capacity alone cannot tell you whether a backpack is suitable. Two bags with the same liter rating can have different shapes, strap ranges and torso fits—and two children of the same age can need very different sizes.

Use liters to narrow the options. Make the final decision with the backpack packed and on the child.

 

What Does Backpack Capacity Actually Measure?

A backpack’s liter rating describes its approximate internal volume. It tells you how much space the compartments provide, but not how the backpack will fit.

A short, wide 14L bag may sit very differently from a tall, narrow 14L bag. Thick padding, internal dividers and pocket design can also change how much of that volume is useful.

Capacity therefore answers one question:

Is there enough room for the intended items?

It does not answer:

Does the backpack match the child’s torso?

Do the shoulder straps adjust far enough?

Does the bottom hang too low?

Does the bag move when the child walks?

Is the loaded backpack comfortable?

Those questions matter more than the number printed on the product page.

Do Not Choose a Kids’ Backpack by Age Alone

Age charts are convenient, but children of the same age can have different heights, torso lengths and levels of strength.

A backpack should be proportional to the individual child. The American Academy of Pediatrics recommends a correctly sized backpack with two broad adjustable shoulder straps and a chest or waist strap, worn close to the body. Read the AAP backpack guidance.

Instead of beginning with “What size does an eight-year-old need?”, begin with:

What will the child actually carry?

How long is the outing?

What extra equipment must the adult carry for the family?

Does the loaded backpack fit this child today?

Age can provide context, but it should not overrule real fit.

When a Backpack Under 10L May Be Enough

A very small daypack can work for a short nature walk, park visit or easy outing where an adult carries the group equipment.

It may hold:

A small water bottle

One snack

A sun hat

A whistle

A thin personal layer

The benefit is a naturally limited load. There is less temptation to add unnecessary items.

The tradeoff is limited flexibility. A bottle and jacket can quickly fill the main compartment, particularly when the bag has thick padding or several small pockets. A pack under 10L may also be outgrown sooner if its strap range and back length are very small.

Choose it when the child only needs a few personal essentials and the adult is prepared to carry everything else.

 

When a 10L Backpack Makes Sense

Around 10L is a practical starting point for lightweight family outings.

It can provide enough room for water, a snack, a compact rain layer and one or two small personal items without encouraging a heavy load.

A 10L pack may work well when:

The hike is short and conditions are predictable

The child is new to carrying a backpack

An adult carries first aid, navigation, extra water and spare family clothing

The child’s personal jacket is light and compressible

Keeping the load simple matters more than having spare space

However, “10L” does not guarantee a child-sized fit. Check the back length and adjustment range just as carefully as you would with a larger bag.

When a 14L Backpack May Be the Better Choice

A 14L kids backpack offers more flexibility without automatically becoming a large hiking pack.

The extra space can help when the child needs to carry:

A water bottle

Snacks

A lightweight rain jacket

A warmer layer

Hat and gloves

A whistle

A trail notebook or small personal item

It can also make packing easier. Clothing does not need to be compressed as tightly, and water or snacks may remain easier to reach.

A 14L pack may be reasonable for a longer family day outing, changeable weather or a child whose personal clothing occupies more room. But the extra four liters should create breathing room—not an instruction to add more weight.

If the bag is too long for the child’s torso, swings while walking or requires the shoulder straps to be tightened to their limit, 14L is not the right size even if the capacity looks useful.

 

10L vs. 14L Kids Backpack

Neither capacity is automatically better. The right choice is the one that holds the planned personal load while remaining stable on the child.

When a Backpack Larger Than 14L May Be Appropriate

Some older or larger children may comfortably use a pack above 14L, especially for longer outings, cold-weather clothing or structured outdoor programs.

But additional capacity should have a specific purpose.

Before moving to a larger bag, ask:

What does not fit in the current backpack?

Is that item truly the child’s responsibility?

Could the adult carry it instead?

Will the larger bag still sit within the child’s back?

Is the larger pack heavier before anything is added?

For an ordinary family day hike, adults should retain the group’s navigation, first-aid supplies, emergency equipment, backup clothing and additional food or water. The National Park Service advises prepared adults hiking with children to carry essentials including water, snacks, sun protection and appropriate clothing. See the NPS guidance for hiking with kids.

A larger backpack is useful only when the fit and the actual equipment justify it.

 

Fit Can Make a Smaller Backpack Feel Larger

A properly fitted backpack is easier to carry than a poorly fitted bag with the same load.

With the intended items inside, check that:

Both shoulder straps sit evenly

The pack stays close to the body

The chest strap sits across the upper chest, not the neck

The bottom does not hang far below the waist

The child can move both arms freely

The bag does not swing from side to side

Nothing hard presses into the back

Pack heavier items close to the back and balance the left and right sides.

For a complete fit checklist, read Best Hiking Backpack for Kids: What Parents Should Check First.

 

Test the Size With Real Gear

An empty backpack test is not enough.

Fill the bag with the exact water, food and clothing planned for the hike. Adjust both shoulder straps and the chest strap, then let the child walk for at least ten minutes.

Ask them to:

Walk normally

Go up and down stairs

Bend down

Reach both arms forward

Take out their water or snack

Remove and put the pack on again

Watch for leaning forward, shoulder straps sliding outward, repeated strap pulling or the bag bouncing against the lower back. These are stronger signs than the child saying the pack feels fine for a few seconds.

If the backpack becomes uncomfortable, first remove equipment. Do not assume the solution is always a different capacity.

Leave Room Without Filling It

Some empty space can be useful.

It allows a jacket to be packed without perfect folding, makes snacks easier to reach and gives an adult somewhere to place an item temporarily. The backpack does not need to be completely full to be the correct size.

At the same time, a half-empty bag that hangs too low is not a good fit simply because it is light.

Aim for enough usable space, a secure shape and a load the child can forget about while walking.

What Should the Parent Carry?

The child’s pack should contain a small set of personal items. The parent’s backpack should carry the equipment the group relies on.

That normally means the adult retains:

First-aid supplies

Navigation and emergency communication

Extra water and food

Backup clothing

Weather protection

Any emergency shelter or safety equipment appropriate to the route

For parents using a compact daypack, Is a 19L Backpack Big Enough for a Day Hike? explains what a 19L backpack can realistically hold and when more capacity is needed.

The family packing system should still work if the child becomes tired and the adult needs to carry both backpacks.

 

A Simple Kids Backpack Size Checklist

Before choosing between 10L, 14L or a larger pack, ask:

Does it hold the child’s planned personal items?

Does the back length match the child?

Can both shoulder straps be adjusted correctly?

Does the chest strap sit in the right place?

Is the empty backpack reasonably light?

Does it remain stable with water inside?

Can the child reach or identify important items?

Is there a little spare room without encouraging overpacking?

Can an adult take over the bag easily?

If the answer to the fit questions is no, the liter rating does not matter.

Final Thoughts

There is no single backpack capacity for every child.

A pack under 10L may be enough for a short nature walk. Around 10L can suit simple family outings. A 14L backpack provides more room for layers and longer day plans, while larger packs should be chosen only when the child’s size, comfort and actual equipment justify them.

Start with what the child needs to carry. Choose a backpack that fits those items and the child’s body. Test it with real gear before reaching the trail.

The right size is not the backpack with the most growing room.

It is the one that lets the child carry a small part of the day comfortably while the adult remains responsible for the family’s shared equipment and safety.