When the DM is tracking party movement, diagonal movement will be counted as 1“ for every odd “square” of diagonal movement, and 2” for every even “square” of diagonal movement. So, one square of diagonal movement is 1“, two squares is 3”, three is 4“, four is 6”, and so on.

If movement consists of a mix of cardinal and diagonal movement, only diagonal movement should be considered when determining whether a “square” of movement costs 1“ or 2”.

This same rule is applied if a map or grid is used for combat positioning. This rule is not applied if using a hex grid.

Here is a more complex example:

You can see that for the 9th square of movement, the diagonal move cost 2“ since the last diagonal move (on square 5) only cost 1”.