I have the feeling that a checkerboard must be simple to create in Photoshop, perhaps using layers and duplicating checkerboard elements, but I am still struggling.
First thing that comes to my mind is to define a 2 x 2 square pattern, then use Edit - Fill - Pattern.
When I am doing that sort of thing as a one off (and I do this quite often) I turn on the grid. If the grid spacing is not to my liking, I open the Image resize panel > turn off resampling, and change the dpi. I find this easier than changing the grid spacing in Preferences.
You could do what you like from there.
If that sounds long winded, I promise it is verr very quick to do, but I'd like to have an Array tool similar to Autocads. You can make arrays using Free Transform shift and repeat, but I have to think how to do that almost every time I use it. Or you can use Scripts if you know how, or use a ready made one like this panel by Trevor Morris:
Trevor, if you draw all the squares of a checkerboard then do 'Edit > Define Pattern...', the pattern definer will cleverly discard almost all your work and make an optimal tile containing only the repeating element of 2 squares x 2 squares.
You get the same tile for far less work by doing what Noel said - define only a 2 squares x 2 squares pattern tile and do a Fill or make a Pattern Fill Layer with it.
I didn't know that conroy, but I almost always do it long hand anyway, because it really doesn't take me very long, and I feel more in control of the process. I am usually designing on the fly as well, so like to see how things devlop, rather than commit to a sellected space and filling it.
this worked beautifully for me, thanks
I agree with pattern. Pattern 2x2 is not the only solution, you can create larger "pixels" if you need like 4x4, 8x8 and so on... Use transparency or fill "transparent" pixels with gray color.