What Is 1/2 Cup + 1/3 Cup

So, you’re staring into your kitchen cabinet, a half-cup measuring scoop in one hand and a third-cup in the other, and you realize: you need to add them together. Maybe you’re baking cookies for a party, or trying to impress a date with homemade mac and cheese. Either way, you’ve stumbled into a math problem that feels like a personal attack.

Let’s be honest: fractions are the reason I didn’t become an astronaut. “One half plus one third?” my brain screams, then immediately suggests moving to a country that only uses metric cups. But fear not. I’ve bribed a mathematician with coffee, and we’re about to crack this nut wide open.

The Quick Answer (For the Impatient)

One half cup plus one third cup equals five-sixths of a cup. That’s ⅚, written in fancy fraction-speak. In human terms: it’s a little less than a full cup, but a lot more than a half cup.

Think of it this way: if a full cup of coffee costs $5, you’re paying $4.17 for this mountain of ingredients. Five-sixths isn’t scary—it’s just the fraction equivalent of “almost all the way there.”

Why This Feels Harder Than It Should Be

Your brain wants to add 1 + 1 and get 2, but fractions are stubborn rule-followers. You can’t just jam ½ and ⅓ together like they’re Lego blocks—they have different-shaped bottoms. The bottom number (the denominator) is where the disagreement lives.

Half-cup says “I’m two equal parts of a whole,” while third-cup scoffs, “I’m three equal parts, you peasant.” They’re speaking different languages. To make them add up, you need a common denominator—a kind of diplomatic translator.

The secret is finding a number both 2 and 3 can divide into evenly. And guess what? That number is 6. (Surprise! You’ve just rediscovered the word “six.”) So ½ becomes 3/6, and ⅓ becomes 2/6. Add those together, and you get 5/6. Boom. Math.

A Visual Trick That Won’t Hurt Your Brain

Take a full cup of water. Pour it into six equal imaginary puddles—each puddle is one-sixth of a cup. Now, three of those puddles equal a half cup. Add two more puddles for the third cup. Count your puddles: you have five. That’s five-sixths of a cup. See? No calculators were harmed.

In real life, this means you’ll need to measure ½ cup, then add ⅓ cup. But if you don’t have a ⅓ cup measure, just eyeball it: fill the half-cup about 80% of the way, then top it up a little more. Your ancestors made do without measuring tools—they used “a handful” and “that looks about right”. You’ll be fine.

What If You Can’t Find a ⅚ Cup Measure?

News flash: 5/6 cup measures do not exist. They’ret he unicorns of the baking world. But you have options. One: use a 1-cup measure, fill it to the five-sixths mark. Two: cheat with tablespoons. Since 1 cup equals 16 tablespoons, 5/6 cup equals 13.33 tablespoons. That’s 13 tablespoons + 1 teaspoon. (Yes, 3 teaspoons per tablespoon—welcome to the circus.)

Or, my favorite option: use a liquid measuring cup with clear lines. Fill to 2/3 cup, then add 2 tablespoons. That’s exactly 5/6 cup. Problem solved. You can now return to your life.

Surprising Facts to Make You Sound Smart

Did you know that fractions used to be a form of ancient torture? Actually, no—but the Babylonians used base-60, not base-10, which is why we have 60 minutes in an hour and 360 degrees in a circle. They were obsessed with fractions. They’d have loved your ½ + ⅓ problem.

Also, in Japan, schoolchildren learn fractions by folding origami paper. So if you mess up your measuring, just blame the paper crane you didn’t make. Another fun fact: the word “denominator” comes from the Latin for “naming thing” while “numerator” means “counting thing.” So the bottom names the size of the piece, and the top counts them. Now you know.

A Plea for Sanity

Look, cooking is supposed to be fun, not a pop quiz from a cruel math teacher. If you accidentally add a full cup instead of 5/6, your cookies will be a bit drier and your mac and cheese a bit looser—but nobody will die. The world will not end. Your guests will just say, “Huh, interesting texture,” and eat it anyway.

So take a deep breath. Measure your ½ cup, then your ⅓ cup, dump them in a bowl, and stir. You have successfully performed a miracle of applied mathematics. Go ahead, high-five yourself. You earned it.

And next time someone asks, “What’s ½ cup + ⅓ cup?” you can look them dead in the eye, smile, and say: “That, my friend, is five-sixths of a cup—and a whole lot of confidence.” Then walk away before they ask about metric conversions.