Mass and volume describe different things

Mass describes how much matter a sample contains. Volume describes the space it occupies. A large container can hold a small mass of a light material or a much larger mass of a dense one.

Similar words can hide different quantities

An ounce of mass belongs with pounds and grams. A fluid ounce belongs with liters and cups. The word “ounce” in both names does not make them interchangeable.

Our Weight category uses familiar everyday wording for mass. It does not calculate weight as a gravitational force. The Volume category measures capacity and space.

Density connects mass and volume

Density is mass divided by volume. To calculate a mass from a volume, you need the density of the material in consistent units. There is no universal cups-to-grams factor for all ingredients.

How a material is packed also matters. A loosely filled cup of flour and a compressed cup of flour need not contain the same mass. For repeatable cooking results, use the measurement method the recipe specifies.

Choose tools around the quantity

A scale is appropriate when the recipe specifies mass. A graduated container is appropriate when it specifies liquid volume. Keep that distinction in mind during recipe calculations: a unit converter can change the unit within either quantity, but it cannot supply missing information about the ingredient.