---
title: "How do you count the hidden cubes in a cube counting puzzle? | Once Books"
description: "Count layer by layer from the bottom, then add the cubes that must sit under every raised cube. Nothing floats in a fair puzzle, so hidden cubes are always accounted for."
source: "https://www.oncebooks.com/answers/how-do-you-count-hidden-cubes-in-a-cube-counting-puzzle"
---

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3. How do you count the hidden cubes in a cube counting puzzle?

Answer

# 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](https://www.oncebooks.com/glossary#hidden-cube) 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](https://www.oncebooks.com/spatial-puzzles/cube-counting), which print with the total on the second page.

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[Spatial puzzle generator Count the cubes, draw the views or build the solid, and print the answer. Free, no sign-up. Try it free](https://www.oncebooks.com/tools/spatial-puzzle-generator)

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