What's 1/3 Cup Plus 1/3 Cup

Let’s be honest: the first time you stared at a recipe demanding “⅓ cup plus ⅓ cup,” your brain probably did a tiny somersault. You might have blinked, Googled it, or just winged it with a shaky hand and a prayer. Don’t worry—we’ve all been there, standing in the kitchen like a confused math wizard without a wand.

The simple truth is that ⅓ cup plus ⅓ cup equals ⅔ cup. Yes, it’s that straightforward. Two thirds of a cup is just a little more than half, which is lucky, because your measuring cup set probably has a half-cup mark that you can squint at and say, “Close enough.”

Why Your Brain Fights This Math

Fractions have a way of making us feel like we’re back in fourth grade, sweating over a pop quiz. We see ⅓ and think “tiny,” but add two of them together, and suddenly you’ve got a massive pile of chocolate chips or a dangerously full liquid measuring cup. It’s like a carpentry trick: two short boards become one medium board.

The real shocker? ⅔ cup is exactly 10 tablespoons plus 2 teaspoons. If you’ve ever tried to measure ten tablespoons, you know it looks like a small bathtub for a gerbil. But for baking, that precision matters, especially if you’re making cookies that don’t want to turn into frisbees.

A Quick History of Third Cups

Surprising fact: the standard U.S. cup measurement was invented by a woman named Fannie Farmer in the 1890s. Before her, people just threw handfuls of flour at each other. Fannie basically said, “Let’s not ruin dinner with guesswork,” and the ⅓ cup was born. So when you measure ⅓ plus ⅓, you are honoring a legacy of women who hated burnt toast.

Now, if you’re using a dry ⅓ cup measure—the little plastic scoop that lives in your drawer—just scoop twice and dump. If you’re using a liquid measuring cup, pour two ⅓-cup lines, and you’re golden. Pro tip: do not use a soup ladle. I tried that once. The result was a cake that looked like a failed science experiment.

What Happens If You Get It Wrong?

I’ll tell you. I once used ½ cup plus ½ cup because I was too lazy to read my own handwriting. The cookies turned into one giant cookie pancake. It was delicious, but my family looked at me like I was a culinary heretic. Getting ⅔ cup right makes the difference between a scone and a rock. If you add too little, your batter will be dry and crumbly—like a desert that forgot to rain.

But here’s a surprising fact from actual kitchen science: water, flour, and sugar all weigh different amounts per cup. One ⅓ cup of flour weighs about 40 grams, but ⅓ cup of sugar weighs about 65 grams. So ⅓ cup plus ⅓ cup of sugar is way heavier than flour. Your recipe doesn’t care about weight, but your arms will when you lift the mixing bowl.

The Emergency Backup Plan

What if your ⅓ cup measure is missing? Maybe the dishwasher ate it, or your toddler turned it into a hat. You can use a ¼ cup plus one tablespoon plus a teaspoon. That’s right: ¼ cup = 4 tablespoons, and ⅓ cup = 5 tablespoons + 1 teaspoon. Add twice that, and you’ve got your ⅔ cup. Boom—math saved the day again.

Or, just use a ½ cup measure and fill it almost to the brim. I call that the “good enough for pancakes” method. It’s not precise, but pancakes forgive almost everything except fire.

The Psychological Win

There is a deep, primal satisfaction in knowing that you have successfully combined two equal parts into a larger whole. It’s a tiny victory for order in a chaotic world. You aren’t just measuring ingredients—you are affirming that the universe is logical. Plus, you get to eat whatever comes out of the oven.

And if you ever need to double that? Like, what’s ⅓ cup plus ⅓ cup plus ⅓ cup? That’s a whole cup. Congratulations, you are now a fraction wizard. Use your powers only for good—and for banana bread.

The Takeaway

So the next time a recipe says “⅓ cup plus ⅓ cup,” do not panic. Do not call your mom. Do not run to the internet and type furiously. Just grab your trusty ⅓ cup, scoop twice, and move on with your delicious life. Math is your friend, and so is this article.

And remember: if you mess up, you can always call it “rustic.” That’s what I do. I once made a pie where the crust looked like a topographical map of the Grand Canyon. Guess what? Everyone called it “artisanal.” You are never more than one excuse away from victory.