Rolled Oats — Cups to Grams Conversion 1 cup of rolled oats = 90 grams. 0.25 cups22.5 g0.5 cups45 g0.75 cups67.5 g1 cups90 g1.5 cups135 g2 cups180 g3 cups270 g4 cups360 g Open the Cooking Converter for more ingredients