A mass of 225 grams of self-rising flour is equivalent to 1.8 cups. This amount is roughly equal to 1 cup with an additional 12.8 tablespoons to measure out the 0.8 cups left over.
The density of self-rising flour is 125 grams per cup. One takes the mass of the self-rising flour as measured in grams and divides it by 125 in order to calculate the volume of the flour in cups. When using metric measurements for volume, 225 grams of self-rising flour is equal to 425.86 milliliters.
Self-rising flour (known as "self-raising flour" in the United Kingdom) is regular flour that has already been mixed with baking powder and salt.