Quick Answer
No, 1 cup is not always the same as 8 oz. However, for some ingredients like water and other liquids, 1 cup is very close to 8 oz in volume. For dry ingredients like flour, sugar, etc. there can be a bigger difference between 1 cup and 8 oz depending on factors like how finely it is ground, how settled it is in the cup, and environmental humidity. Generally, 1 cup of a dry ingredient weighs between 4-8 oz.
Measuring Cup Sizes
When following recipes, it’s important to pay attention to whether quantities are specified by volume (cups, teaspoons, etc.) or by weight (oz, grams, etc.). Using the right measuring tools and technique for the ingredient will give you the most accurate results.
Here are the approximate volumes for common measuring cups in the U.S. customary system:
| 1 teaspoon (tsp) | = 1/3 tablespoon (tbsp) | = 1/48 cup | = ~5 mL |
| 1 tablespoon (tbsp) | = 3 teaspoons | = 1/16 cup | = 15 mL |
| 1 fluid ounce (fl oz) | = 2 tablespoons | = 1/8 cup | = 30 mL |
| 1/4 cup | = 4 tablespoons | = 12 teaspoons | = ~60 mL |
| 1/3 cup | = 5 tablespoons + 1 teaspoon | = 16 teaspoons | = ~80 mL |
| 1/2 cup | = 8 tablespoons | = 24 teaspoons | = ~120 mL |
| 2/3 cup | = 10 tablespoons + 2 teaspoons | = 32 teaspoons | = ~160 mL |
| 3/4 cup | = 12 tablespoons | = 36 teaspoons | = ~180 mL |
| 1 cup | = 16 tablespoons | = 48 teaspoons | = ~240 mL |
Standard measuring cups in the U.S. are designed to hold the above volumes. However, there can still be some variance between different cup sets based on factors like manufacturing tolerances and wear over time with use.
When measuring liquids like water, milk, oil, etc. the volume conversions are quite accurate. 1 cup of water weighs about 8 oz.
For dry ingredients, weights can vary more for an equivalent cup measure based on several factors:
Particle size
Smaller particles like flour fit more densely into a measuring cup than larger particles like chopped nuts. So 1 cup of chopped nuts will weigh less than 1 cup of flour, even though they take up the same volume.
How settled
Some ingredients like sugar and flour settle and compact over time in their packaging or after sifting. 1 cup of freshly fluffed flour will weigh less than 1 cup of flour that has been shaken and settled.
Humidy/moisture
Dry ingredients absorb moisture from the environment. So 1 cup of flour on a humid day will weigh more than 1 cup of flour on an arid day.
Typical Weights for 1 Cup of Common Dry Ingredients
Here are approximate weights for 1 cup measurements of some common dry ingredients:
| All-purpose flour | = ~120 g / 4 oz |
| Granulated sugar | = ~200 g / 7 oz |
| Brown sugar | = ~220 g / 8 oz |
| Confectioners’ sugar | = ~120 g / 4 oz |
| Cocoa powder | = ~100 g / 3.5 oz |
| Cornmeal | = ~150 g / 5 oz |
| Rolled oats | = ~80 g / 3 oz |
| Wheat berries | = ~200 g / 7 oz |
| Rice | = ~185 g / 6.5 oz |
| Coconut flour | = ~80 g / 3 oz |
| Almond flour | = ~95 g / 3.5 oz |
| Chopped nuts | = ~100 g / 3.5 oz |
| Dried fruit | = ~145 g / 5 oz |
| Sliced cheese | = ~110 g / 4 oz |
As you can see, dry ingredient weights range quite a bit for a 1 cup measure depending on the density and other properties of the material.
When Volume vs. Weight Matters
For casual cooking, measuring dry ingredients like flour, sugar, spices, etc. by volume (cups) is usually fine for recipes, since the small variances won’t make a big difference.
However, for baking which requires more precision, weighing dry ingredients is recommended for the most accurate and consistent results.
Going by weight instead of volume ensures you add the right amount of each ingredient and achieve the proper chemical balance for the recipe to turn out as intended. A cup of flour can vary by over 30 grams between a fluffy and settled measure. Over multiple ingredients, those discrepancies compound and can alter the final product.
Here are some examples of baking recipes where weighing dry ingredients is advised:
Bread
The ratio of flour to liquid and leavening agents must be precise to get the proper rise and texture. Too much or too little flour can result in dense, gummy bread.
Cakes
Cakes are very sensitive to getting the right moisture and structure from the flour and other ingredients. Too much flour will make the crumb dry and tough. Too little makes it wet and loose.
Cookies
Getting the right proportion of fat, sugar, and flour impacts how cookies spread and whether they turn out crispy or chewy. A couple tablespoons variance in measuring flour can dramatically change cookie textures.
Pastry
Whether it’s pie crust, croissants, or phyllo dough, the ratio of fat to flour is critical for creating flaky layers. Too much variance in flour weight throws off that delicate balance.
Batters and doughs
The moisture level and density of batters (like pancakes) and yeast doughs are very technique driven. Improper flour or liquid weight can lead to undesirable results.
Tips for Measuring Dry Ingredients
When measuring dry ingredients by volume, follow these tips for best accuracy:
– Use measuring cups and spoons that are sized according to U.S. standards. Over time, check that they still hold the expected amounts.
– Spoon flour and other dry ingredients loosely into the cup, then level off the top using a straight edge like the back of a knife. Don’t tap or shake the cup to settle contents first.
– For brown sugar, pack it down lightly in the cup to fill air gaps. For granulated sugar, don’t pack but make sure it’s settled.
– Set your measuring cup on a level surface as you fill and level it for an even measure.
– Follow any specific instructions in a trusted recipe, like sifting flour before measuring it.
– When halving recipe quantities, don’t just eyeball half a cup in a liquid measuring cup. Use proper sized measuring spoons or cups.
– Use glass or plastic measuring cups for dry ingredients. Don’t use metal as it conducts more humidity.
– Store opened bags of flour and other baking ingredients in airtight containers to minimize humidity absorption.
– Buy a kitchen scale for the most accurate measurements by weight. Look for one that shows both metric and U.S. customary units.
Conclusion
While 1 cup of liquid like water is very close to 8 oz in weight, for dry ingredients 1 cup can equal a range of weights in ounces depending on the food’s density and other properties. Following best practices for measuring by volume gives reasonably consistent results for most home cooking needs. But a kitchen scale removes the uncertainties of measuring cups and is the tool of choice for precision baking.
