100 grams of flour in cups

Flour is light, so 100 grams of it fills about 0.83 of a US cup, close to five-sixths. That is an awkward mark to find, because no measuring cup carries a five-sixths line. It is the first sign that a scale reads this better than a cup does.

Where the cup weight sends the answer

The reverse reading depends on one thing: what a cup of flour weighs. The charts do not settle on a single figure. King Arthur weighs a level cup at 120 g, so 100 g is 0.83 of a cup. The USDA weighs the same cup at 125 g, which drops 100 g to 0.80. A popular baking blog scoops a cup straight from the bag to 161 g, and by that weight 100 g is barely three-fifths. One weight of flour, three cup readings, none of them a line you can pour to.

Where the cup weight sends the answer
A cup of flour weighsUS cups
King Arthur, 120 g0.83
USDA, 125 g0.80

We build this page on King Arthur's 120 g, the weight American recipes are written against. The flour master page sets both authorities side by side and gives the reason for the pick.

Why five-sixths is a problem

A measuring cup carries lines at a half, a third, a quarter. It has nothing at five-sixths. To hit 100 g by eye you fill past the three-quarter line and hope, and flour punishes the guess: pack a 120 g cup down and it holds a third more without a mark on the rim to warn you. Grams hold still. That is the whole case a reverse conversion makes for itself, one weight in and one volume out, with no scooping style left to argue about.

Other flour weights in cups

The same reading for the weights a recipe is likely to name:

Other flour weights in cups
FlourUS cups
50 g0.42 cups
100 g0.83 cups
150 g1.2 cups
200 g1.7 cups
250 g2.1 cups

The same 100 grams is not always this awkward. It falls on a near-clean half for granulated sugar and lands just under a stick for butter. Double the weight and 200 grams of flour is one and two-thirds of a cup.

Questions about 100 grams of flour

Is 100 grams of flour half a cup?
No, it is more than that. Half a US cup of all-purpose flour weighs about 60 g, so 100 g runs to roughly 0.83 of a cup.
How many cups is 100 grams of flour?
About 0.83 of a US cup on King Arthur's 120 g cup, or 0.80 on the USDA's 125 g. Both land on a fraction no cup carries a line for, so treat either as a guide.
Why do sites give different cups for 100 grams of flour?
Because each starts from a different weight for the cup. King Arthur uses 120 g, the USDA 125 g, and some blogs a scooped 161 g; a heavier cup means fewer cups for the same 100 g. How you scoop moves it again.

Sources

King Arthur Baking for the 120 gram cup and USDA FoodData Central SR Legacy for the 125 gram cup, the two figures this reverse reading is built on. Charlotte's Lively Kitchen for the 161 gram scooped cup cited as the heavy end. Full citations on the sources page.