You can measure 2/3 cup by measuring out its equivalent in ounces (5 1/3), pints (1/3) and tablespoons (10 plus 2 teaspoons). If you do not have any measurement tools, then you can use the size of your fist to measure about one cup; cut that amount into thirds, and discard one third.
- Consider equivalent measurements
The equivalent of 2/3 cup is 5 1/3 fluid ounces, 1/3 pint and 10 tablespoons plus 2 teaspoons. Knowing these equivalent measurements allows the use of other types of measuring devices, like a liquid measuring cup or measuring spoons.
- Estimate based on known sizes
The size of your fist or a baseball is about one cup. You can estimate a measurement based on that size, cut it into thirds, and discard one third.
- Look for package markings
Packages of ingredients, like butter and cream cheese, often include measurement markings. Simply cut the product along the marking for a perfect measurement.