Rucksacks. Litre size confusion

[Paul]

Thanks bucket, but why the discrepancy?
In your case, 16 liters would have been 25x25x25cms. or some variation round that theme.
Was that the bag size?

The junk I carry only weighs in at 7 kgs but bag, tarp, clothing, etc, is bulky so that's why I need a bigger size. It currently fits into a knackered old 30 litre bag BUT even then the bag size by maths (HxWxD) is 41 litres.