Calculations are based on ratio between areas of walls and squares.
Light infill is 17% full.
Square size is 3.70mm and line thickness is 0.35mm.

Medium infill is 22% full.
Square size is 2.65mm and line thickness is 0.35mm.

Solid infill is 39% full.
Square size is 1.25mm and line thickness is 0.35mm.

Full infill is 75% full.
Square size is 0.35mm and line thickness is 0.35mm.

Some other useful information about infill: http://support.zortrax.com/hc/en-us/articles/201809922-Z-Suite-Manual#%23poptions