In the United States, most ingredients in cooking are measured by volume with cups and spoon sizes. The ingredients in recipes from some countries like the United Kingdom, however, are given in terms of weight or mass. Because different ingredients have different densities, their volumes weigh different amounts. Converting between cups and grams can be necessary when baking an American recipe in the United Kingdom or analyzing the nutritional information of ingredients.
One cup of all-purpose white flour is 125 g, or a density of 125 g/cup. To determine how many grams of flour to use in a recipe, multiply 125 by the number of cups required. Remember that 1/4 cup is 0.25 cups, 1/3 cup is 0.33 cups and 1/2 cup is 0.5 cups. This results in the following conversions: 1/2 cup = 62 g; 1/3 cup = 42 g; 1/4 cup = 31 g.
One cup of granulated white sugar or packed brown sugar is 200 g, or a density of 200 g/cup. To determine how many grams of sugar to use in a recipe, multiply 200 by the number of cups required. You can also calculate the following conversions: 1/2 cup = 100 g; 1/3 cup = 67 g; 1/4 cup = 50 g.
One cup of salted butter is 227 g, or a density of 227 g/cup. To determine how many grams of butter to use in a recipe, multiply 227 by the number of cups required. For smaller amounts, use the following conversions: 1/2 cup = 114 g; 1/3 cup = 76 g; 1/4 cup = 57 g.
Honey and Syrups
One cup of honey and other syrups like molasses is 339 g, or a density of 339 g/cup. To calculate how many grams of honey to use in a recipe, multiply 339 by the number of cups required. For smaller amounts, use these conversions: 1/2 cup = 170 g; 1/3 cup = 113 g; 1/4 cup = 85.
Some ingredients, like salt or baking powder, use much smaller amounts than a cup. These are better converted from tablespoons and teaspoons. There are 16 tbsp. in a cup, and there are 3 tsp. in a tablespoon. Salt has a density of 18 g/tbsp., or 6 g/tsp. Baking powder has a density of 12 g/tbsp., or 4 g/tsp.
Finding Densities and Conversion Information
All food packaging in the United States includes nutrition information on the label, which tells how many grams are in a serving size as well as in the entire package. To convert from cups to grams, multiply the cups in the recipe by the number of total grams in the container, then divide this result by the total cups or spoon sizes in the container. Some websites, such as Nutritiondata.self.com, have searchable databases for foods, including conversions on how many grams are in a cup, tablespoon or teaspoon.