Recipes rely on the use of accurate measurements, so knowing how to correctly measure 2/3 of a cup is necessary to achieve the desired outcome. Or if you're in the middle of preparing a recipe and your 2/3 measuring cup is nowhere to be found, it is helpful to know measurement conversions so that your recipe turns out as expected. Being aware that there is a difference in how different types of ingredients are measured and how to measure them appropriately will aid in achieving recipe success.
How to Measure 2/3 of a Cup
Dry ingredients are measured using measuring cups, which are often made of plastic or metal. Dry ingredients include flour, sugar, nuts and chocolate chips. To accurately measure 2/3 of a cup of a dry ingredient, fill the measuring cup slightly over, then sweep a spatula handle or other kitchen utensil with a flat handle across the top of the cup to remove the excess.
For coarser ingredients like nuts or chocolate chips, jiggle the measuring cup to settle the pieces, then use your best judgment to determine if the cup is approximately full, adding or removing pieces as needed.
You may also want to double check the recipe. If it references a "generous" or "heaping" cup, then that means you don't need to level off the measurement. Keeping a little extra on top is fine.
“Sticky” Dry Ingredients
Ingredients such as molasses, honey or peanut butter, while not technically dry ingredients, are also measured with measuring cups. When measuring these types of "sticky" dry ingredients, you can use a flat edge to level off the cup, or for stickier ingredients, it may be easier to eyeball it. Set the cup on a flat surface and position yourself with a line of sight that is level with the top of the measuring cup. You want the ingredient to be approximately level across the top.
Dry Ingredients Substitution
Use a 1/3 of a cup and fill it twice if you don't own or can't find your 2/3 measuring cup. You can also use 10 tablespoons plus 2 teaspoons in a pinch as a conversion for 2/3 of a cup.
Liquid ingredients are measured using liquid measuring cups, which are often made of plastic and come in sizes like 4 or 8 cups. Most include a 2/3 cup measurement marking. To accurately measure a liquid ingredient, like water, olive oil or soup stock, slowly pour it into a liquid measuring cup that is set on a flat surface. As you approach the 2/3 cup line, position yourself so that you are eye-level with the marking. Due to the surface tension of liquids, the surface does not sit perfectly flat. If forms a meniscus, which appears as a slight curve, slowly continue adding your liquid to the measuring cup until the bottom of the meniscus is perfectly level with the bottom of the 2/3 cup marking.
Liquid Ingredient Substitution
In a pinch, you can use 10 tablespoons plus 2 teaspoons as a conversion for 2/3 of a cup, though an accurate measurement will be more difficult to achieve due to the meniscus. Rest the spoon on a flat surface and level your sight with the top of the spoon to make sure the liquid isn't curving too far under or over the top of the spoon.
Sticks of butter typically come packaged with markings that show tablespoons. A stick of butter equals 8 tablespoons. If you need 2/3 of a cup of butter, use 1 whole stick of butter, plus approximately 3 tablespoons from another stick.