How Much Is 2/3 of a Cup? | The Measurement That Stumps

2/3 of a cup equals 10 tablespoons and 2 teaspoons, or roughly 158 milliliters and 5.3 fluid.

You pull out a recipe that calls for 2/3 cup of flour or milk, then open the cabinet and see standard measures: 1/4, 1/3, 1/2, and 1 cup. That 2/3 slot is missing, and suddenly a simple step turns into a small kitchen math puzzle.

The honest answer is straightforward: 2/3 cup breaks into familiar units you already own. This article walks through the exact conversions, the easiest ways to combine what you have, and a few tricks for getting it right without a special measure.

The Exact Numbers Behind 2/3 Cup

Splitting a third from a half is the core confusion. A full cup holds 16 tablespoons, so 2/3 of that lands at 10 tablespoons plus 2 teaspoons. That’s the number most home cooks reach for when a 2/3 cup mark is missing.

In metric, 2/3 cup equals approximately 158 milliliters. In fluid ounces it lands at roughly 5.3 ounces. For context, 1/2 cup is 118 ml and 3/4 cup is 177 ml, so 2/3 sits neatly in between.

Knowing these numbers means you can reach for a liquid measure or a tablespoon set without needing a dedicated cup. The math stays the same whether you are measuring water, sugar, or oil.

Why 2/3 of a Cup Trips Up Most Cooks

Standard measuring cup sets skip 2/3 because the fraction doesn’t divide evenly into the common 1/4-, 1/3-, and 1/2-cup increments. Most recipes call for halves or quarters, so manufacturers default to what is used most often. When 2/3 appears, people guess or try to eyeball, which leads to inconsistent results.

• Two 1/3 cup measures: The simplest workaround — just fill your 1/3 cup twice. This is the fastest route when you have that size in your set.
• 1/2 cup plus 2 tablespoons and 2 teaspoons: If you only have a 1/2 cup, top it off with exactly 2 tablespoons and 2 teaspoons. That combination adds up to 2/3.
• 10 tablespoons and 2 teaspoons directly: Use a tablespoon measure ten times, then add two teaspoons. This works well for dry ingredients like sugar or cocoa powder.
• Kitchen scale by weight: For dry ingredients, weighing is the most accurate method. 2/3 cup of all-purpose flour typically weighs about 80 to 85 grams, depending on how you scoop.

The key is knowing which tools you already have. Most kitchens own at least one of these combinations, so you can skip the frustration and measure with confidence.

Common Substitutions for Measuring 2/3 Cup

No measuring cups at all? A standard dinner spoon holds roughly 1 tablespoon, and a typical teaspoon holds 1 teaspoon. That means you can count out 10 heaping dinner spoonfuls and two level teaspoonfuls. For liquid, a common coffee mug often holds between 8 and 12 fluid ounces — you can fill it roughly two-thirds of the way for a close approximation, though it will not be as precise.

For reference, a 2/3 cup measurement equals about 158 milliliters, a number that the Exploratorium’s conversion table confirms. Sticking with known volume measures is usually easier than guesstimating with random cups.

These conversions hold for both liquid and dry ingredients by volume. Weight will vary by ingredient, so a scale is the best way to replicate baker‑precise results.

How to Measure 2/3 Cup Without a Dedicated Cup

If your set lacks a 2/3 cup and you do not own a scale, these step‑by‑step methods will get you the right amount every time. Choose whichever fits the tools you have on hand.

1. Use the 1/3‑cup twice. Scoop and level a 1/3 cup, dump it in your bowl, then repeat. This is the fastest method and requires no math.
2. Combine 1/2 cup with extra spoons. Fill a 1/2 cup, then add 2 tablespoons and 2 teaspoons. The 1/2 cup gives you 8 tablespoons, and the extra 2 tablespoons plus 2 teaspoons get you to 10 total.
3. Go all‑spoon. Count out 10 level tablespoons, then add 2 level teaspoons. For dry ingredients, level each spoonful with a straight edge like a knife.
4. Use a scale for dry ingredients. Look up the typical gram weight for your specific ingredient — all‑purpose flour is roughly 80–85 g, granulated sugar is about 133 g per 2/3 cup.

Each method works because they rely on known standard measures. The trick is to avoid compressing flour or packing brown sugar unless your recipe specifically calls for it.

Dry vs. Liquid: Does the Method Change?

Volume is volume when you are measuring liquids — water, milk, oil, or broth can be poured into any cup and read at eye level. Dry ingredients behave differently because they can settle or clump. Fluffing flour with a fork before scooping prevents it from compacting, which would make your 2/3 cup too heavy.

For brown sugar, the rule flips: many recipes ask you to pack it firmly into the cup. That means you scoop, press down, and add more until the cup is full, then level the top. A packed brown sugar cup can weigh nearly 50% more than an unpacked one, so follow your recipe’s lead.

One of the easiest ways to remember the base conversion is to note that theharvestkitchen’s measurement chart lists 10 tablespoons and 2 teaspoons as the standard equivalent. That figure works for any ingredient you are measuring by volume.

Weights vary by how you scoop and the brand of flour or sugar. For baking, a scale removes the guesswork entirely, but the volume conversions above will still produce a reliable 2/3 cup.

The Bottom Line

2/3 of a cup is simply 10 tablespoons and 2 teaspoons, about 158 ml, or two 1/3 cups. You do not need a special measure — just a tablespoon, a teaspoon, and one of the common combos already in your drawer. The next time a recipe calls for 2/3 cup, you have all the options without hunting for a missing piece of equipment.

If you bake often, a kitchen scale makes future fractions even easier — just zero out the bowl and pour until the grams match your ingredient’s chart.