Self-Rising Flour

One US cup of self-rising flour weighs 120 grams. Going the other way, 100 grams is about 0.83 cups.

Also called self rising flour, self-raising flour, self raising flour, sr flour, biscuit flour.

TL;DR: 1 cup of self-rising flour weighs 120 grams. High confidence, based on convergence across White Lily, Gold Medal, Great Value, and King Arthur's own homemade-recipe guidance. This is one of the rare flour entries where King Arthur agrees with producer labels — no correction needed.

Self-rising flour is base wheat flour with baking powder and salt already mixed in. The composition is typically 1 cup (120 g) of flour, 1½ teaspoons (about 6 g) of baking powder, and ¼ to ½ teaspoon (about 1.5 to 3 g) of table salt. The added leavening and salt total roughly 7 grams per cup, but they dissolve into interstitial air gaps between flour particles rather than displacing volume, so the finished blend packs at the same density as the base flour: 120 grams per US cup.

Two regional styles dominate the US market and produce different baking results despite sharing the same bulk density. Southern-style self-rising flour, made from 100 percent soft winter wheat, has protein content around 8 percent and produces the light, flaky biscuits associated with Southern baking. White Lily is the flagship brand for this style and has been the dominant Southern retail product since 1883. Northern or national-brand self-rising flour, made from all-purpose flour (blended hard and soft wheat), has protein content around 10 to 11 percent and produces slightly denser, chewier baked goods. Gold Medal, Pillsbury, and Great Value use this approach. King Arthur does not sell a pre-blended self-rising flour but publishes a homemade recipe that starts from their standard all-purpose flour, which they also use as the reference for their 120-gram-per-cup figure.

The source data converges cleanly at exactly 30 grams per quarter-cup serving across every brand I checked. White Lily's nutrition label matches Gold Medal, Great Value, and Walmart house brand, all at 30 grams per 1/4 cup with 100 calories and 22 to 23 grams of carbohydrate per serving. The parallel White Lily All Purpose Flour (USDA Branded Foods entry UPC 032500103011) uses the same 30-gram serving weight, confirming that the added baking powder and salt do not change the bulk density in any measurable way. King Arthur's own blog on self-rising flour explicitly states 'To make homemade self-rising flour, whisk together 1 cup (120g) all-purpose flour, 1 1/2 teaspoons baking powder, and 1/4 teaspoon table salt,' which agrees with the producer convergence.

Some online references cite 125 grams per cup for self-rising flour, notably Wikipedia and several generic conversion sites. This appears to be a rounded reference figure derived from an older USDA reference for wheat flour in general, rather than from producer label data. The producer labels consistently show 120 grams per cup, so that is the figure used here.

For practical baking, use 120 grams per cup, and remember two things when substituting self-rising flour for regular all-purpose flour in a recipe. First, omit any baking powder and salt the recipe calls for, because they are already in the flour. If the recipe also calls for baking soda, leave that in; baking soda is separate from baking powder and provides additional lift and browning. Second, self-rising flour loses potency over time as the baking powder degrades. A bag more than six months past its purchase date will produce noticeably flatter baked goods and should be replaced. For best results, store self-rising flour in an airtight container in a cool, dry place and use within six months of opening.