# Sudoku has 6.6 thousand trillion possible layouts > For classical Sudoku, the number of filled grids is **6,670,903,752,021,072,936,960** (6.671×10²¹), which reduces to **5,472,730,538** [essentially different solutions](https://www.wikiwand.com/en/Mathematics_of_Sudoku#Essentially_different_solutions) under the validity preserving transformations. ## Road signs - [[Combinatorial explosion beats exponential growth]] --- Source: [The Mathematics of Sudoku - Wikipedia](https://www.wikiwand.com/en/Mathematics_of_Sudoku)