Creating a new Map the Right Size
I am looking at covering an old map to CC3
This map atm it realy just a test map, so I can get the hang of CC3, but as this is mostly what I will be doing once I've got the hang of it, I want to get it right from the start.
The problem I am having is getting the map & grid the right size.
The old map is on a grid.
Each square is = 300 ft (grid size: 0.0567)
Map is 45 vertical squares ≈ 3.69 miles, and 65 horizontal squares ≈ 2.56 miles
Unless my math is wrong
For some reason I keep ending up 10 squares short both horizontal & vertical.
Why would this be happening?

Comments
What size are you putting in the new map wizard when you generate the map, and then what settings are you giving the grid when you create it?
I set them as the following
Opps: Above I did type this backwards, hence why it is now flipped, I did not do make this error in CC3.
Horizontal as 3.69, Vertical as 2.56, grid size as 0.0567
If the tutorial I was watching is correct I need to set these in miles
Note that the new map wizard isn't designed to handle fractional map units (even though the program itself does), so trying to input those values would result in a map 3 by 2 units. You'll need to create it as 4 by 3 units and manually resize if you need it that exact or just accept the little bit of extra.
At that scale, you may also consider mapping in feet and not miles, but that does include a bit more of setup when starting with an overland template, so I won't recommend doing that until you get a bit more familiar
I originally wanted to set it to feet, but realized that was out of my skill set.
Extra is fine and players will are unlikely to go to the edges, except the east side it would be better to have the extra space. so that words.
Thanks, for the quick replys and help.