Denise, It measures 9 inches by - let me look; it's in my media section - 9 inches by 6 inches by 2 inches. (external measurements) How much batter to use depends on how thick you want the soap. For a spin swirl, I would not fill such a mold to the top as it would spill out with the spinning, so 1 inch thick or so would be best. As to the batch size, this would make approximately a pound and a half of soap at 1 inch thick. For calculations, of course, one needs to measure the inside of the mold, but I don't have it with me, so I guesstimating the approximate measurements for calculation. Using the standard dimensions times each other, then times 0.42, the amount of oil would be somewhere around 18 or 19 ounces of oil, which pretty much comes out to about 500 grams, which is, I believe what I used the last time I used the mold, and the total batch size would be around 750 grams, which is about a pound and a half or more, depending on lye concentration.