You're standing in the kitchen, flour on your jeans, looking at a recipe that demands 2/3 cup of softened butter. You look at the sticks in your hand. They're marked with those little lines for tablespoons, but the math just isn't mathing quickly enough while the oven preheats. Most people just guess. They eyeball it. Then they wonder why their cookies turned into flat, greasy puddles or their cake came out weirdly crumbly.
So, let's get the math out of the way immediately. How many tablespoons are 2/3 cup of butter? The answer is 10 tablespoons plus 2 teaspoons.
It sounds specific because it is. If you're using standard U.S. sticks of butter, you're looking at one full stick (which is 8 tablespoons) plus another 2 tablespoons and 2 teaspoons from a second stick.
The Math Behind 2/3 Cup of Butter
Measuring fat is the most common place where home bakers mess up. Honestly, it's not even your fault. The U.S. imperial system is basically a collection of riddles designed to make us fail 5th-grade math.
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To understand why we land on 10 tablespoons and 2 teaspoons, you have to break down the base units. A single cup contains 16 tablespoons. If you divide 16 by 3 to get those thirds, you get a messy decimal: $5.333$. Since nobody has a "0.333 tablespoon" measuring spoon in their drawer, you have to convert that remainder into teaspoons.
There are 3 teaspoons in a single tablespoon. So, $0.333$ of a tablespoon is exactly 1 teaspoon.
Double that for a 2/3 cup measurement, and you get $10.66$ tablespoons. That $0.66$ translates to 2 teaspoons.
A Quick Visual Cheat Sheet
- 1/3 cup: 5 tablespoons + 1 teaspoon
- 2/3 cup: 10 tablespoons + 2 teaspoons
- 1 cup: 16 tablespoons
If you’re working with a scale—which, truthfully, you should be—this is way easier. In the world of professional pastry chefs like Pierre Hermé or Claire Saffitz, volume is a dirty word. A cup of butter isn't always a cup of butter because of air pockets or how cold the fat is when you pack it into the measuring tool. On a digital scale, 2/3 cup of butter weighs 151.5 grams. Round it to 152 grams and your heart will keep beating just fine.
Why Getting This Right Actually Matters for Your Bake
Butter isn't just a flavor carrier. It's a structural engineer.
When you cream butter and sugar together, the sugar crystals grate against the solid fat, creating millions of tiny air bubbles. These bubbles expand in the heat of the oven. If you accidentally throw in 11 tablespoons because you "felt like it was close enough," you’ve changed the ratio of fat to flour. Too much butter leads to "spreading." This is why your chocolate chip cookies might look like thin lace instead of chewy discs.
On the flip side, if you're shy with the measurement—maybe you only did 10 tablespoons and skipped the teaspoons—your baked goods might turn out dry. Butter provides moisture and "shortens" gluten strands (that's why we call it shortening). Less butter means longer gluten strands, which means a tougher, breadier texture in things that should be tender.
The Stick Butter Problem
Most butter in American grocery stores comes in 4-ounce sticks.
One stick = 1/2 cup = 8 tablespoons.
Two sticks = 1 cup = 16 tablespoons.
When you need 2/3 cup of butter, you are essentially using 1 and 1/3 sticks.
I’ve seen people try to cut a stick into thirds by eye. Don’t do that. It’s a trap. Our eyes are terrible at judging volume in 3D cylinders or rectangles. Use the markings on the wrapper as a guide, but remember that those wrappers can shift during packaging. If the paper is crooked, your measurement is crooked.
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Softened vs. Melted: The Volume Trap
Here is something most blogs won't tell you: 2/3 cup of cold butter and 2/3 cup of melted butter don't always occupy the same space in a measuring cup.
When butter melts, the water content (usually about 15-18% in American butter) can separate, and the air trapped in the solid fat escapes. If a recipe calls for "2/3 cup butter, melted," you should measure the 10 tablespoons and 2 teaspoons while it's solid, then melt it.
If the recipe says "2/3 cup of melted butter," they usually mean you should melt a bunch of butter and then measure out the liquid. It's a subtle distinction, but in chemistry—which is all baking is—subtlety is the difference between a win and a trash can full of burnt dough.
European vs. American Butter
If you’re splurging on Kerrygold or Plugra, you’re dealing with higher butterfat content. American butter is legally required to be 80% fat. European styles are usually 82% to 85%. While the tablespoon count (10 tbsp + 2 tsp) remains the same for 2/3 cup of butter, the results will be richer. Higher fat means less water, which means less steam. Your pastry might be flakier but slightly less "puffy."
Common Misconceptions About Kitchen Conversions
People often think that 2/3 is "halfway between 1/2 and 3/4." It’s not.
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Mathematically:
- 1/2 cup = 8 tablespoons
- 2/3 cup = 10.6 tablespoons
- 3/4 cup = 12 tablespoons
If you just split the difference and use 10 tablespoons, you are still nearly a full teaspoon short. In a small batch of shortbread, that’s enough to make the dough crumble before it ever hits the pan.
I once talked to a commercial baker who told me that the number one reason home recipes fail is "the spoon scoop." People scoop butter with a spoon into a cup and leave air gaps at the bottom. To get an accurate 2/3 cup without a scale, you have to pack that butter down like you're building a sandcastle. Smash it in. Level the top with a flat knife.
Practical Steps for Your Next Recipe
If you are tired of looking up "how many tablespoons are 2/3 cup of butter" every time you make brownies, do yourself a favor and memorize the 10 + 2 rule.
- Use a Scale: Stop measuring by volume. 151.5 grams is 2/3 cup. It’s faster, cleaner, and you don't have to wash a greasy measuring cup afterward.
- Check the Wrapper: If you must use sticks, use one full stick and then use the markings on the second stick to cut at the 2-tablespoon mark. Then, add a "heavy" teaspoon (two actual teaspoons) to the mix.
- Temperature Check: Ensure your butter is at the temperature the recipe specifies. If it calls for "room temperature," it should be about 65°F. It should dent when pressed but not be shiny or oily.
- The Liquid Trick: If you are measuring weird fractions of butter, some people use the water displacement method. Fill a measuring cup to 1 cup with water, add butter until the water hits 1 and 2/3 cups, then pour the water off. It works, but it's messy and kind of a pain.
Most importantly, stop stressing the tiny decimals. While 10 tablespoons and 2 teaspoons is the "perfect" answer, baking is a craft of averages. If you get within a gram or two, your family will still eat the cookies. But knowing the exact conversion gives you the control to troubleshoot when things go wrong.
Actionable Next Steps:
Grab a permanent marker. Open your kitchen cabinet. Write "2/3 cup = 10 tbsp + 2 tsp" on the inside of the door or on the lid of your flour bin. You'll never have to wash the flour off your hands to check your phone for this conversion again. If you're currently mid-recipe, go ahead and cut that second stick just past the two-tablespoon line and find your smallest measuring spoon for the final two teaspoons. Your dough consistency will thank you.