How many mm tall is a 1 gallon water container?
If were take the Imperial gallon and work with 4.54609 litres we can see that if the container were to have a square base of 10 x 10 centimetres then each centimetre of height would be 10 x 10 x 1 = 100 cubic centimetres and we would need a container which was 45.4609 cm tall. That would equate to 454.609 milimetres tall.