You're standing in the kitchen. Flour is everywhere. You’ve got a recipe that calls for a two-thirds cup of sugar, but your measuring cup set is missing that specific size. Maybe it's at the bottom of the dishwasher, or maybe you just never owned one. You look at your tablespoons. You look at the bowl. You start wondering: how many tablespoons 2/3 cup requires to get the job done without ruining dinner.
It's 10 tablespoons plus 2 teaspoons.
That’s the short answer. If you’re in a hurry, grab your tablespoon, level off ten of them, and then add two little teaspoons. You're done. Go bake. But if you care about why your cookies sometimes spread like pancakes or why your bread ends up as a brick, stick around. There is actually a lot of math—and some weird historical baggage—hiding in that measurement.
Why 2/3 Cup is the Most Annoying Measurement in Baking
Most measuring cup sets come with a 1/4, 1/3, 1/2, and 1 cup. The 2/3 and 3/4 cups are often the "luxury" items in a set. When they’re missing, you have to do mental gymnastics. The problem is that the US Customary System isn't based on 10. It’s based on 16.
Since there are 16 tablespoons in a full cup, trying to divide that by three gives you a repeating decimal. $16 \div 3 = 5.3333$. So, one-third of a cup is 5 tablespoons and one teaspoon. When you double that to find out how many tablespoons 2/3 cup contains, you get 10 tablespoons and 2 teaspoons.
If you try to just round down to 10 tablespoons, you are missing about 10 milliliters of volume. In a delicate souffle or a precise macaron, that's a disaster. In a beef stew? It doesn't matter at all. Honestly, the "close enough" mentality is what separates great bakers from people who just make edible stuff.
The Math Breakdown for the Skeptics
Let’s look at the numbers. Most people don't realize that a tablespoon is exactly three teaspoons. This is the "Golden Ratio" of the American kitchen.
- 1 Cup = 16 Tablespoons
- 1/3 Cup = 5 Tablespoons + 1 Teaspoon
- 2/3 Cup = 10 Tablespoons + 2 Teaspoons
If you want to get really nerdy, we can talk about fluid ounces. A cup is 8 fluid ounces. Therefore, 2/3 of a cup is roughly 5.33 fluid ounces. If you have a liquid measuring cup with "oz" markings but no 2/3 line, aim just a hair above the 5 oz mark.
Liquid vs. Dry: The Trap Everyone Falls Into
Don't use a coffee mug. Don't use a "big spoon" from your silverware drawer. Those aren't real measurements.
When you are figuring out how many tablespoons 2/3 cup equals, you also have to consider what you are measuring. A tablespoon of honey weighs way more than a tablespoon of flour. But volume is volume, right? Technically, yes. But the way you measure changes.
If you use a dry measuring cup (the metal or plastic ones you dip into a bag) for milk, you’re going to spill it before you reach the mixing bowl. If you use a liquid measuring cup (the glass ones with a spout) for flour, you’re almost certainly going to pack the flour down, using way too much. Professional bakers like King Arthur Baking or the late, great Julia Child always advocated for scales for this very reason.
Why Your Tablespoons Might Be Lying to You
Not all tablespoons are created equal. In the US, a tablespoon is 14.8 ml. In the UK, it’s often 15 ml. In Australia, a tablespoon is actually 20 ml (they use 4 teaspoons per tablespoon!).
If you’re following an old Australian recipe and you use 10 American tablespoons to hit that 2/3 cup mark, you’re going to be significantly short on ingredients. Always check the origin of your recipe. Most modern digital recipes will specify, but those old handwritten cards from your grandma might be using "heaping" measurements, which basically throws all the math out the window.
The "Shortcut" That Usually Works
Sometimes you don't want to count out 10 individual tablespoons. It's tedious. You lose track around tablespoon six because the dog barked or the kids started screaming.
Here is the hack: use the 1/3 cup twice.
It sounds stupidly simple, but people forget it. If you don't have a 1/3 cup, use a 1/3 cup scoop from your protein powder or even a cleaned-out yogurt container if you’ve pre-measured it.
Another way? Use 1/2 cup and then add 2 tablespoons and 2 teaspoons.
- 1/2 cup = 8 tablespoons.
- 8 tablespoons + 2 tablespoons = 10 tablespoons.
- Add the final 2 teaspoons.
- Boom. 2/3 cup.
Does Temperature Matter?
Kinda. If you're measuring 2/3 cup of melted butter versus cold, solid butter, the volume changes slightly. But more importantly, the accuracy of your tablespoon measurement changes.
Measuring 10 tablespoons of cold butter is easy—just look at the markings on the wrapper. Each stick is 8 tablespoons (1/2 cup). So for 2/3 cup, you need one full stick plus another 2 tablespoons from a second stick. Plus those pesky 2 teaspoons.
But if the butter is melted? It’s much harder to measure 10 tablespoons without making a greasy mess. In that case, use a liquid measuring cup and hit that 5.33 oz mark.
Professional Insight: The Weight Factor
If you want to stop guessing how many tablespoons 2/3 cup is forever, buy a $15 kitchen scale.
A "cup" of flour can weigh anywhere from 120 grams to 160 grams depending on how hard you pack it. If a recipe asks for 2/3 cup of flour, you're looking for roughly 80 to 90 grams. If it's sugar, it's closer to 135 grams. Once you start baking by weight, you realize that tablespoons are actually a pretty chaotic way to run a kitchen. It's like trying to measure the length of a football field using a handful of blueberries.
Common Conversion Mistakes to Avoid
- The "Heaping" Spoon: Unless the recipe says "heaping," use a knife to level off the top of the tablespoon. An extra "dome" of baking soda can make your cake taste like soap.
- The "Eye-baller": You think you know what 2/3 looks like in a 1-cup measure. You don't. Humans are notoriously bad at estimating volume in cylindrical containers.
- The Dessert Spoon Confusion: Don't use the spoons you eat cereal with. Those are not "tablespoons" in the culinary sense. They are usually closer to 2 teaspoons in volume.
Practical Application: The 2/3 Cup Cheat Sheet
If you’re in the middle of a recipe right now, here is exactly what to do based on what tools you have left in your drawer:
- Only have a Tablespoon? Level off 10, then add 2 teaspoons.
- Only have a 1/4 Cup? Use two of them, then add 2 tablespoons and 2 teaspoons. (This is annoying, just find a bigger spoon).
- Only have a 1/3 Cup? Fill it twice.
- Only have a 1/2 Cup? Fill it once, then add 2 tablespoons and 2 teaspoons.
- Only have a scale? Aim for 150ml or 158 grams (for water/milk).
Actionable Steps for Better Baking Results
Stop relying on volume for everything. While knowing how many tablespoons 2/3 cup is helps in a pinch, your baking will improve 100% if you move toward weight-based measurements.
Start by calibrating your own tools. Fill your 2/3 cup with water and pour it into your 1-cup measure. See where it hits. Then, take that same water and see how many of your "tablespoons" it takes to empty it. You might find your "tablespoon" is actually a bit small.
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If you are stuck with a recipe that is failing, check the humidity. Flour absorbs moisture from the air. On a swampy day in Florida, 2/3 cup of flour weighs more than it does in a dry Vegas winter. This is why that 10 tablespoons and 2 teaspoons rule is a solid baseline, but your eyes should always be on the texture of the dough or batter.
Keep a small conversion chart taped to the inside of your pantry door. Include the 2/3 cup conversion specifically, because it’s the one that trips everyone up. Instead of pulling out your phone with floury fingers, you can just glance at the door. Use a permanent marker. Write it big. 10 Tbsp + 2 Tsp = 2/3 Cup. Your future self will thank you when the oven is preheating and the pressure is on.
Invest in a "odd-size" measuring cup set. Several brands, like Prepworks or OXO, sell sets that specifically include a 2/3 and a 3/4 cup. It eliminates the math entirely. It's the best $10 you'll ever spend if you bake more than once a month. No more counting spoons. No more second-guessing. Just scoop and pour.