The Grid Calculator InDesign plug-in is by the way awesome because it not only calculates the grid but also sets the whole thing up in InDesign ready to go and ready to be saved for later use. … But it is also possible to play with number of columns and rows and fiddle with the units in the Margin section to let everything fit and the measurements for the margins are calculated at the same time.
calculator
The Grid Calculator
It means you can leave Grid Calculator and paste the information into the document you are working on and don’t have to go back and forth to copy one field at the time. … So, if you are ready to jump on the grid bandwagon, read my articles about grid making in Illustrator and use the Grid Calculator to speed up the process.