Size Guide

Pick a capacity, not a name

Bag names are marketing. Litres are not. Use this as a starting point.

Capacity	Best for	Roughly holds
15 – 22L	Daily commute, day hikes	Laptop, lunch, layer, water bottle
25 – 32L	Overnight, long day out	One change of clothes, laptop, toiletries
35 – 45L	Carry-on travel, 3 – 5 days	Four outfits, shoes, laptop, wash kit
50L+	Trekking, week-long trips	Sleeping bag, cooking kit, full wardrobe

US cabin baggage limits

Most US carriers allow a cabin bag of 22″ x 14″ x 9″ plus a personal item of roughly 18″ x 14″ x 8″. Budget carriers are stricter — check before you fly. A 40L pack usually fits the cabin allowance; a 45L pack usually only fits when it is not fully expanded.

Measuring your laptop

Laptop sleeve sizes refer to screen diagonal, not body size. A 15.6″ sleeve fits most 15″ and 16″ machines; check the width if you carry a larger-chassis gaming laptop.

Torso length matters for trekking packs

For packs over 45L, the fit is set by torso length, not height. Measure from the bony bump at the base of your neck to the level of the top of your hip bones. Under 18″ is a short back; 18 – 20″ regular; over 20″ long.