How do you count the hidden cubes in a cube counting puzzle?
Updated 21 September 2026
Count the visible cubes one layer at a time from the bottom up, then add the cubes that must be underneath each raised cube to hold it up. In a fair puzzle nothing floats and the shape is one connected piece, so every tall column stands on a full stack of cubes you cannot see.
The mistake most people make is to count what they can see and stop. The rule that makes a cube counting puzzle solvable is that every cube rests on another, so a cube three layers up tells you there are two cubes beneath it, whether or not they are drawn. Work the base first, then each column’s height, and add the hidden cubes column by column.
Our puzzles are graded by how many cubes are hidden: a few at easy, 40 or more at hard and 70 or more at expert. Practise on the free cube counting puzzles, which print with the total on the second page.