How to Accurately Size a Print Image?

[defaulth6m35ubgh2ld]

I am trying to print a grid onto different sized Paper 24x24 inches and 36x36 inches.

How would I properly size it so that each grid square is a partiular size? 

How would I preview what the image will look like on the larger piece of paper?

The grid is a pre made image.

[Semaphoric]

What are the dimensions in pixels of the image? Is the image a full sheet of a grid?

You would likely be doing this by changing the resolution (without resampling) for print.

[defaulth6m35ubgh2ld]

With the grid I am working with now the dimensions in pixels is:

1400x1400

Resolution= 100 pixels/inch

Grid is 100x100 squares

[JJMack]

What Aspect Ratio do your image have do the math. you can use menu View>New Guide Layout... the plare with row and columns keeping in mind your Images  Aspect Ratio like 16 4x4 on 2' x2' canvas or 24 6"x9" on 3'x3' canvas.

Do the math.