One cup of all-purpose flour is the equivalent to 128 grams, or 4.5 ounces. Half a cup of all-purpose flour is equal to 64 grams or 2.25 ounces, and a fourth of a cup is equal to 32 grams or 1.13 ounces. These measurements also apply to confectioners sugar.
Other types of flour, like bread flour, have different measurement conversions. One cup of bread flour is equal to 136 grams or 4.8 ounces; therefore, a half a cup is equal to 68 grams or 2.4 ounces, and a fourth of a cup is equal to 34 grams or 1.2 ounces.
Other cooking materials have different gram measurements when they are measured into one cup. Butter, for instance, is equal to 227 grams when measured into one cup. A half a cup of butter is equal to 113.5 grams. A fourth of a cup is equal to 56.75 grams. A cup of rolled oats is equal to 85 grams or 3 ounces. A cup of granulated white sugar is equal to 201 grams or 7.1 ounces. A cup of packed brown sugar is equal to 220 grams or 7.75 ounces, and a cup of honey, molasses or syrup is equal to 340 grams or 12 ounces.