Quick answer: For day hikes, REI lists kids daypacks at 5 to 20 liters. For an overnight, fit matters more than capacity: measure the child torso length as you would an adult, choose a pack with an adjustable torso in a youth or extra-small size, and keep the load light. REI gives no weight rule for kids, so err on the light side and let adults carry the heavy gear.
Twelve-year-olds vary a lot in size, so a pack labeled for kids may or may not fit. Torso length is the number to measure.
This guide covers day packs, overnight packs and how to fit them.
Related: tent camping gear checklist, measuring torso length and what to carry.
Day Hikes
REI puts kids daypacks at 5 to 20 liters. That holds water, snacks, a layer and a few Ten Essentials. A school pack can work for short, easy hikes.
Overnights
| Step | Guidance |
|---|---|
| Measure torso | C7 vertebra to the iliac crest line, per REI |
| Choose size | Youth or extra-small with an adjustable torso so it grows with them |
| Capacity | Often 30 to 50 liters, the REI weekend range, but fit comes first |
| Load | Light: sleep gear and clothes; adults carry the tent, stove and most food |
Fit Check
- Load the pack with a few pounds and loosen all straps.
- Set the hipbelt on the hip bones.
- Snug the shoulder straps; REI says they should wrap without carrying much weight.
- Check that the load lifters angle back around 45 degrees.
Honest Limits
Children grow quickly and tolerate weight differently. This gives the fit method, not a weight limit; a pediatrician or scout leader can advise on load for a specific child.
Frequently Asked Questions
What size daypack for a 12-year-old?
5 to 20 liters, per REI kids daypack range.
What size for an overnight?
Fit by torso length; capacity often 30 to 50 liters.
Can a kid use an adult pack?
If the torso length fits. Extra-small adult packs sometimes do.
How much should a child carry?
REI gives no figure. Keep it light.
What should the child carry?
Sleep gear, clothes, water and snacks.
Should the pack have a hipbelt?
Yes, so the hips carry the load.
How do I measure torso?
C7 to the line across the top of the hip bones.
Will they outgrow it?
An adjustable torso extends the life.
Is a school backpack okay?
For short day hikes, yes.
What if they complain of sore shoulders?
Re-fit the hipbelt and reduce weight.
Bottom Line
Day packs for kids run 5 to 20 liters; overnight packs are fit by torso length.
Keep the load light and the hipbelt on the hips.
Sources: REI, How to Choose Daypacks; REI, Backpack Fit: Torso and Hip Size; REI, How to Choose a Backpack.