I'm guessing 4" x 4"

Do you think a kitchen 3'x8' will look too busy with a checkered floor with 6"x6" tiles?

No I think it will look great. You need the small scale tiles to get the full impact of the checkerboard. Otherwise you'll just have a row of black (diamond) tiles down the middle, framed by two rows of white tiles. This isn't what appeals to you, I think.

I also am quite crazy about black and white checkerboards and I have saved dozens of pictures (actually any time I run across one I save it!) for future reference. Eventually I want my entrance hall to have a floor like this. It's really hard to find small scale tiles, though, so I'm glad you've located the 6"x6" ones. Good luck! This will be beautiful.

Thanks for your quick response Cynthia! I'm actually planning to have a diamond pattern of black and white marble cut to size, however since the tiles come as 12"x12", the most economical approach is to cut them into 4 (6"x6") tiles each. I just don't want it to look like a bathroom. The alternative 8"x8" approach would create a lot of waste.

By all means have the tiles cut into quarters. Once the cuts are made they'll end up a little under 6" square, but then with grout they'll "grow" back to that dimension! I'm so excited for you! No it will NOT look like a bathroom. It will be stunning :)

It's funny because in the past few years tiles have been getting bigger and bigger until I can't imagine them any larger (24" x 36" is one I saw last week!). You know what happens when they can't move any further in one direction--they go in the opposite. I'll bet you anything in a few years you'll be seeing tiles down to very small sizes and it will be heralded as the next new look! You will already be there, with your fabulous 6"x6" tiles which just happen to be the very best choice for the scale of your kitchen floor anyway. You will be sitting pretty.

It's been lovely "conversing" with you, Gillian!