How this calculator works
Choose a density that describes the actual substance, then enter its volume to calculate mass. Inverse volume mode divides known mass by density. The rectangular option measures a solid block from three dimensions. This is useful for liquids, metal stock and ingredient conversions, but a volume measure alone cannot identify mass. A cup of loose flour and a cup of water have very different masses. For food, powders, foams and alloys, use a measured or product-specific density that matches packing, temperature and composition. The reference table gives a few rounded examples rather than a universal ingredient database.
Formula
rho = m/V; m = rho V; V = m/rho; rectangular solid V = length x width x height.
Worked example
At a measured density of 800 kg/m3, 250 mL has mass 0.2 kg, or 200 g. Conversely, 600 g of the same substance occupies 750 mL. Check whether your volume measure is a US cup, legal cup or a metric millilitre measurement before converting a recipe.
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Frequently asked questions
Why does the substance matter?
Mass equals volume times density. Equal volumes of different substances can contain different amounts of matter.
Can I convert cups to grams?
Yes, if the selected volume unit and density describe your ingredient. Packing can change food bulk density substantially.
Can I use an unpacked ingredient density for a packed cup?
Use a bulk density measured with a similar packing method. Compression changes the amount of material in a fixed cup volume.