It depends on the ingredient: 300 g of granulated sugar is 1.5 cups and 300 g of butter is 1.32 cups. Every common ingredient is in the chart below.
Converter
2.4 cups
Measure: about 2⅓ cups + 1 tbsp
Type a number — fractions like 3/4 or 1 1/2 work too.
300 grams in cups, by ingredient
US cups. The measure is the nearest you can make with a standard set of cups and spoons.
300 grams in US cups for each ingredient
Ingredient
Cups
Measure
All-purpose flour
2.4
≈ 2⅓ cups + 1 tbsp
Granulated sugar
1.5
1½ cups
Butter
1.32
≈ 1⅓ cups
Powdered sugar
2.5
2½ cups
Brown sugar (packed)
1.36
≈ 1⅓ cups
Milk
1.23
≈ 1¼ cups
Water
1.27
≈ 1¼ cups
Rice (uncooked)
1.62
≈ 1½ cups + 2 tbsp
Rolled oats
3.7
≈ 3⅔ cups + 1 tbsp
Cocoa powder
3.49
≈ 3½ cups
By weight, 300 g is 10.6 oz whatever the ingredient.
Where these numbers come from
All-purpose flour: 125 g per cup — FDC ID 168894, “Wheat flour, white, all-purpose, enriched, bleached”, portion “1 cup”.
Granulated sugar: 200 g per cup — FDC ID 169655, “Sugars, granulated”, portion “1 cup”.
Butter: 227 g per cup — FDC ID 173430, “Butter, without salt”, portion “1 cup”.
Powdered sugar: 120 g per cup — FDC ID 169656, “Sugars, powdered”, portion “1 cup unsifted”.
Brown sugar (packed): 220 g per cup — FDC ID 168833, “Sugars, brown”, portion “1 cup packed”.
Milk: 244 g per cup — FDC ID 171265, “Milk, whole, 3.25% milkfat, with added vitamin D”, portion “1 cup”.
Water: 237 g per cup — FDC ID 173647, “Beverages, water, tap, drinking”, portion “1 serving 8 fl oz”.
Rice (uncooked): 185 g per cup — FDC ID 168877, “Rice, white, long-grain, regular, raw, enriched”, portion “1 cup”.
Rolled oats: 81 g per cup — FDC ID 173904, “Cereals, oats, regular and quick, not fortified, dry”, portion “1 cup”.
Cocoa powder: 86 g per cup — FDC ID 169593, “Cocoa, dry powder, unsweetened”, portion “1 cup”.
Everything else is worked out from those figures: spoons from 1 cup =
16 tablespoons = 48 teaspoons, and ounces and pounds
from their exact definitions (1 oz = 28.349523125 g, 1 lb = 453.59237 g, NIST).