Rice flour

One US cup of rice flour weighs between 128 and 158 grams, depending on how the cup is filled and which source measured it. That range is the answer; a single number would not be. Every figure behind it is below, with the method each source used.

Rice flour is milled from ground rice grains and comes in three main forms this site groups together: white rice flour (from polished white rice), brown rice flour (from whole-grain brown rice with the bran included), and glutinous or sweet rice flour (from a different variety of rice with a stickier starch composition). The three are physically distinct products and are not substitutes for one another in a recipe.

King Arthur publishes three separate rows in their ingredient weight chart, and the figures diverge meaningfully: white rice flour at 142 grams per cup, brown rice flour at 128 grams per cup, glutinous rice flour at 120 grams per cup. USDA FoodData Central publishes 158 grams per cup for both white rice flour (FDC 169714) and brown rice flour (FDC 168898). USDA does not publish a generic glutinous rice flour entry with a cup portion; the branded records available (Erawan, Pacific Eastern, Bob's Red Mill) are aggregated manufacturer labels, which are treated as reference material rather than authoritative sources on this site. Glutinous rice flour is therefore deferred pending a rigorous second source.

For white rice flour, the two figures are 10.7 percent apart, just over the 10 percent tolerance we apply to the milled category. The variation is consistent with what we see across other flours: USDA's higher figure reads like a dip-and-sweep measurement (scoop into the bag, level off), while King Arthur's lower figure reads like a spoon-and-level (spoon into the cup, level off). Neither source names its method explicitly. We publish the range 142 to 158 grams per cup rather than a single figure.

For brown rice flour, the disagreement is larger at 21 percent — well outside the milled tolerance. Brown rice flour includes the bran, which is coarser and more irregular than the endosperm alone. Both the method variation and the particle-size variation contribute to the spread. We publish the range 128 to 158 grams per cup.

Rice flour is not the same as rice starch, which is the extracted starch component from rice with the protein removed. Rice starch is denser and finer than rice flour and is not covered by this entry. Rice flour is also not the same as rice cereal or ground cooked rice, both of which are hydrated and behave more like a paste than a flour.

Glutinous rice flour, when we can source it properly, will be added as a third state. It weighs less per cup than white rice flour because the starch structure of glutinous rice produces a slightly less dense powder when milled. King Arthur's 120 grams per cup is a plausible figure but requires corroboration.

Rice flour's category is 'milled' because it behaves like other fine milled powders in a measuring cup — it clumps, bridges over air pockets, and its density depends significantly on how it was scooped. The 10 percent tolerance we apply to milled ingredients is genuinely tested here: neither state's two sources agree within it.

Neither the FDA nor the Codex Alimentarius publishes an identity standard or a density specification for rice flour. FDA covers rice flour under 21 CFR Part 137 (cereal flours), addressing enrichment rather than physical properties.

A home baker whose recipe is sensitive to rice flour weight should weigh rather than measure, and prefer whichever source is closer to the recipe writer's own reference. For gluten-free baking, where rice flour blends form the backbone of many mixes, weighing every component is standard professional practice.