Casting Mixing Calculator

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Notes and Common Questions

Volume versus mass

Most manufacturers of casting medium, such as concrete, list mixing ratios as volumetric — meaning you can simply use a scoop, measuring cup, or similar to mix to the specified ratio. Depending on how compacted your medium is, it's possible that using volumetric measurements will result in slight differences in mixed consistency. You may need to add additional water or medium to your final mix.

Units of measure

In our calculator, we use milliliters (ml) for liquid measurements and cubic centimeters (cc) for solids. It's worth noting a few common conversions. One gram of water is the same as one cubic centimeter of water is the same as one milliliter of water. Because of varying densities, the same cannot be said for other materials, and we list non-liquid measurements as "cc" intended to be measured by volume.

Additionally, you may notice that the sum of water and medium combine to equal more in cubic centimeters than the mold volume. This is due to the specific volume of the mixed medium and that we are using simplified volumetric ratios.


The final consistency of your mix should generally be similar to cake batter.