The number of blocks in a square meter depends on the size of each block. Because the square meter is a measurement of area, the length and width of the block must be given in International System of Units notation. The spelling of meter is metre in this notation.

For example, 1 decimeter is ten times smaller than 1 meter. It takes one hundred blocks with an area of 1 square decimeter each to fill 1 square meter. Although 1 meter is just ten times larger than 1 decimeter in linear units, the area is squared, and so the order of magnitude doubles.