Choosing the right backpack size for your adventures isn’t always easy (we get lots of size questions), especially when comparing our 18L, 28L, and 30L waterproof backpacks. While the 18L and 30L share a very similar streamlined design, the 28L has a noticeably different shape and layout, making each pack suited to different types of trips and everyday use.
To help you find the right fit, we’ve put together a side-by-side backpack size comparison, along with a few practical tips and insights to make choosing your next DryTide pack a little easier.
LENGTH: 29cm (11 1/2″)
WIDTH: 13cm (5″)
HEIGHT (backpack closed): 48cm (19″)
HEIGHT (roll down extended): 63cm (24 4/5″)
LENGTH: 30cm (11.8″)
WIDTH: 20cm (7.8″)
HEIGHT: 48cm (18.9″)
This is not a roll down backpack so height is fixed.
LENGTH: 32cm  (12 1/2″)
WIDTH: 17cm (6 3/4″)
HEIGHT (backpack closed): 55cm (21 1/2″)
HEIGHT (roll down extended): 68cm (26″ 2/3)
We calculated the volume of each backpack based on its dimensions. This method proved quite accurate for the more box-shaped 18L and 30L backpacks, but the 28L Point Nemo backpack’s rounded design makes its calculated volume slightly less precise.
To get a more realistic measurement, we also tested the true carrying capacity of each backpack by filling them with water. Here are the results:
The measured volume of the 18L backpack is approximately
20–22L
depending on how tightly you roll down the top closure. Leaving the roll-top fully extended adds even more space, increasing the total capacity by an additional 3–4L when needed (backpack stays opened).
The measured volume of the 28L Point Nemo backpack is approximately
24L
Unlike our roll-top backpacks, the Point Nemo features a fixed-shape design, so its capacity cannot be expanded or adjusted. Its more rounded profile also means the real-world measured volume comes out slightly lower than the calculated volume based on dimensions alone.
The measured volume of the 30L daypack is approximately
29–31L
depending on how tightly you roll down the top closure. Leaving the roll-top fully extended adds even more space, increasing the total capacity by an additional 4–5L when needed (backpack stays opened).
Here you can see all three backpacks photographed together side by side. Especially with the 18L and 30L backpacks the difference in size is subtle from the outside, because they share the same design. Size difference becomes more noticeable once you start packing, the 30L comfortably fits more gear, such as an extra sweater, towel, or additional layers.
For day-long trips or when you need extra space, the 30L backpack is the better choice. For everyday use or for users with a smaller frame, the 18L backpack or the Point Nemo backpack are often the more natural fit. The 28L Point Nemo sits between the two in nominal capacity, but due to its more rounded shape, its usable space feels closer to the 18L. Point Nemo is also the only airtight backpack in the lineup so if you need the highest water protection or if you prefer a zipper closure to the roll down, this is the backpack for you.
Here are examples of people wearing backpacks for real life backpack size comparison. The male model is 182 cm tall (6 ft), and the female model is 174 cm tall (5ft 9″).
