You’re standing in the kitchen, hair a mess, looking at a recipe that calls for a specific measurement, and suddenly you’re staring at a can or a measuring cup wondering how many cups is 13.5 oz. It happens to the best of us. Maybe it’s a can of coconut milk. Maybe it’s a specific brand of broth. You just need the answer so you can get dinner on the table.
The short answer? It is 1.6875 cups.
Of course, nobody has a measuring cup that marks out decimals like that. In the real world of flour-dusted countertops and simmering pots, you’re looking at 1 cup, 11 tablespoons, and 1.5 teaspoons. Or, if you want to be slightly less precise but much faster, it's roughly 1 and 2/3 cups plus a tiny splash.
The Math Behind How Many Cups Is 13.5 oz
Measurements are weird. We use the U.S. Customary System, which feels like it was designed by someone who really liked complicated riddles. To figure this out, you have to know the magic number: 8. There are 8 fluid ounces in a standard U.S. cup.
When you do the math—$13.5 / 8$—you get that 1.6875 figure.
If you’re working with dry ingredients, things get even messier. Fluid ounces measure volume (how much space something takes up), while dry ounces measure weight. A cup of lead weighs more than a cup of feathers, right? The same applies to 13.5 oz of honey versus 13.5 oz of panko breadcrumbs. For the sake of this guide, we are talking about fluid ounces, which is what you’ll find on the side of that coconut milk can or your morning coffee mug.
Why Does 13.5 Ounces Show Up Everywhere?
Have you noticed how many cans are exactly 13.5 oz? It’s not a random number. Thai Kitchen, Goya, and Native Forest all sell coconut milk in 13.5 fl oz (400ml) cans. This is actually a result of the global market. 400 milliliters is a standard metric size used across Asia and Europe. When those products are imported to the U.S., the label gets converted to ounces.
400ml is almost exactly 13.52 fluid ounces. Manufacturers usually just round down to 13.5 on the label to keep things tidy.
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If your curry recipe calls for "one can" of coconut milk, they almost certainly mean this 1.68-cup amount. If you try to use a full 2 cups (16 oz), your sauce might end up too thin. If you only use 1.5 cups, you’re leaving a couple of tablespoons in the can that will probably just sit in your fridge until they grow a science project. Use the whole can.
Breaking It Down Into Smaller Units
Sometimes you don't want to eyeball it. If you need to be exact because you're baking—and baking is basically chemistry where you get to eat the results—you need smaller units.
Basically, 13.5 ounces breaks down like this:
- 1 cup (which is 8 oz)
- 5.5 ounces remaining
To get that 5.5 ounces into something you can actually measure with spoons:
- 4 ounces is a 1/2 cup.
- 1.5 ounces is 3 tablespoons.
So, a very practical way to measure 13.5 oz is 1.5 cups plus 3 tablespoons. It’s much easier to manage than trying to find a "0.6875" line on a plastic pitcher.
Understanding Liquid vs. Dry Measurements
This is where people usually mess up their recipes. Honestly, it's the biggest pitfall in American kitchens.
If you are measuring 13.5 oz of water, milk, or oil, use a liquid measuring cup. You know the ones—the glass or plastic jugs with the spout and the lines on the side. You fill it up, squat down so you're at eye level with the counter, and check the line.
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If you are trying to measure 13.5 oz of flour or sugar, put the measuring cup away. You need a scale.
King Arthur Baking, one of the most respected authorities on flour in the world, points out that a cup of flour can weigh anywhere from 4 to 6 ounces depending on how tightly you pack it. If a recipe says "13.5 oz of flour," and you use a measuring cup to scoop out 1.68 cups, you might actually be using way too much flour because you packed it down. Always weigh dry ingredients if the recipe gives you ounces. 13.5 oz of flour on a scale is always 13.5 oz. 13.5 oz of flour in a cup is a gamble.
Converting 13.5 oz for International Recipes
If you're looking at a British or Australian recipe, be careful. They use the Imperial system, which is different from the U.S. Customary system.
An Imperial fluid ounce is slightly smaller than a U.S. fluid ounce, but their cup is larger (284ml vs the U.S. 236.5ml). If you’re following a recipe from a UK-based creator and they mention ounces, check their "About" page to see which system they use.
For most of the world, 13.5 oz is roughly 400ml. If you have a beaker or a metric measuring cup, just pouring to the 400ml mark is the fastest way to get your 13.5 oz equivalent without doing long division in your head while the onions are burning.
Common Kitchen Items That Hold 13.5 oz
Sometimes you don't have a measuring cup. Maybe you're in a vacation rental or your dishwasher is running.
A standard soda can is 12 ounces. So, 13.5 oz is one full soda can plus about 3 tablespoons.
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A standard tall Starbucks latte (the "Tall" size) is 12 ounces. A "Grande" is 16 ounces. So 13.5 oz sits right in the middle of those two common coffee shop sizes. If you have a reusable water bottle, check the bottom. Many Nalgene or Hydro Flask bottles have ounce markings on the side that are surprisingly accurate for rough kitchen work.
What Happens if You Round Up?
Let's be real. If you’re making a stew and you use 1.75 cups (14 oz) instead of 1.68 cups (13.5 oz), the world isn't going to end. It’s a difference of about one tablespoon. In a big pot of soup, that’s nothing.
However, in delicate custards, soufflés, or specific bread doughs, that extra half-ounce of liquid can change the hydration level. High hydration doughs are sticky and hard to handle. If you're 0.5 oz over on the water, you might find yourself adding more and more flour to compensate, which eventually ruins the texture of the bread. Stick to the 1.5 cups + 3 tablespoons rule for baking.
Quick Reference Conversion List
Since you’re likely in the middle of something, here is the fast breakdown for how many cups is 13.5 oz and its common neighbors:
- 12 oz: 1.5 cups
- 13 oz: 1.625 cups (1 5/8 cups)
- 13.5 oz: 1.6875 cups (roughly 1 2/3 cups + 1 tsp)
- 14 oz: 1.75 cups (1 3/4 cups)
- 16 oz: 2 cups
Practical Steps for Accurate Measuring
To make sure your 13.5 oz measurement is perfect every time, follow these steps.
First, check if the ingredient is liquid or solid. For liquids, use a clear measuring cup on a flat surface. Don't hold it in your hand; your hand shakes and tilts, giving you a false reading.
Second, if you have a kitchen scale, use it. Turn the scale on, place your bowl on it, and hit the "Tare" or "Zero" button. Change the units to ounces. Pour your ingredient until the screen reads 13.5. This is the only way to be 100% accurate, especially with viscous liquids like honey, molasses, or thick yogurt that tend to stick to the sides of a measuring cup.
Third, if you're using the "cup and spoon" method, measure out 1 and 1/2 cups first. Then, add 3 level tablespoons. That will get you exactly to 13.5 ounces.
When dealing with that common 13.5 oz can of coconut milk, give it a good shake before opening. The fat often separates and hardens at the top. If you pour out the liquid first and then try to measure the "cup" portion, you'll get an uneven distribution of fat and water. Shake it, pour it, and you’ll find that the "13.5 oz" on the label matches up perfectly with your 1.68-cup calculation.