It depends on the ingredient: 1½ cups of granulated sugar is 300 g and 1½ cups of butter is 340.5 g. Every common ingredient is in the chart below.
Converter
187.5 g
That is 6.61 oz by weight.
Type a number — fractions like 3/4 or 1 1/2 work too.
1½ cups in grams, by ingredient
One level US cup is 16 tablespoons. The weight depends on what is in the cup.
Recipes write this as 1 1/2 cups, which is easy to misread.
Half a cup (1/2 cup) is a third as much: flour 62.5 g, sugar 100 g, butter 113.5 g.
1½ cups in grams and ounces for each ingredient
Ingredient
Grams
Ounces
All-purpose flour
187.5 g
6.61 oz
Granulated sugar
300 g
10.6 oz
Butter
340.5 g
12 oz
Powdered sugar
180 g
6.35 oz
Brown sugar (packed)
330 g
11.6 oz
Milk
366 g
12.9 oz
Water
355.5 g
12.5 oz
Rice (uncooked)
277.5 g
9.79 oz
Rolled oats
121.5 g
4.29 oz
Cocoa powder
129 g
4.55 oz
By volume, 1½ cups is 24 tablespoons 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).