How Many Ounces Is A Cup of Coffee? This Is Why It Matters

How Many Ounces Is A Cup of Coffee This Is Why It Matters

How Many Ounces Is A Cup of Coffee?

A cup of coffee is a cup of coffee. At least, that’s what most people think. But the truth is, when you buy an 8 oz. cup of coffee, you’re only getting 6 ounces of actual coffee beverage.

While a standard American coffee cup holds 8 ounces, the difference between the metric vs. the imperial system means that a cup of coffee is different sizes around the world. 

In the U.S., a standard coffee cup holds 6 ounces instead of 8 ounces. That’s because medical professionals decided that 6 ounces create a perfect serving size. In most automatic coffeemakers, 6 oz. also equals one cup. While you might use an 8-ounce mug to hold your cup of joe, a coffee machine produces a 6 oz. cup unless you top it off with a new serving. 

Discover how many ounces are in a cup of coffee, how to brew a 6 oz. cup of coffee, and what to expect from coffee cup sizes at popular coffee shops like Starbucks or Dunkin’ Donuts and around the world.

Why Is a Cup of Coffee 6 Ounces Instead of 8 Ounces?

A cup of coffee is 6 oz. instead of 8 oz. because a cup isn’t a standard unit of measurement around the world.

In fact, the United States is one of the few countries to still follow the imperial system compared to the rest of the world (except for Liberia and Myanmar) which uses the metric system of measurement.  

A cup of coffee measures 6 ounces of brewed coffee, even when placed in a larger cup, because previous generations used to drink smaller amounts of coffee. Meanwhile, medical professionals also determined that 6 ounces make the right serving amount for coffee.

This 6 oz. amount of coffee represents how much this liquid portion of brewed coffee measures.

Contrary to popular belief, it doesn’t reflect how much the physical cup can hold. Most standard coffee machines will also produce 6 oz. which equals what we think of as one “cup”.

The 6 oz. brew amount comes from the recommended coffee-to-water that’s considered the golden ratio for a well-brewed cup of coffee.

Keep in mind that there are different coffee pot sizes, which we’ll cover in another article, so coffee sizes may look different if you pour half a pot into an 8 oz. or 12 oz. mug.

Is a Regular Size Cup of Coffee 8 Ounces?

While most regular size coffee cups in America hold 8 fluid ounces, this isn’t the case in the rest of the world. According to the metric system, one cup holds 250 milliliters or around 8.45 fluid ounces.

Here’s where it can get a little confusing. Just because the accepted standard for a coffee cup is 8 fluid ounces (America) or 8.45 fluid ounces (globally) doesn’t mean that that’s how much brewed coffee is poured into the cup.

Because a perfect brew in most drip coffee machines results in around 6 fluid ounces, this is the amount that is typically poured into an 8 oz. or larger cup.

If you’re a serious coffee drinker, you might have twice this amount in a larger size such as an 11- or 15-ounce cup.

Different Systems for Measuring Coffee: Imperial vs. Metric

In the U.S., a notated measuring cup equals 8 ounces, but a cup of coffee is an exception where 6 ounces equals one cup.  

The main difference in coffee cup serving sizes now comes down to the difference in the imperial and metric systems. A metric cup measures at 250ml, while imperial cups hold 284ml.

The truth is that imperial mug sizes aren’t used in most places and are also difficult to purchase.

But even this rule has exception since different kinds of coffee often have different size cups.

For example, several coffee beverages such as espresso shots are measured as one ounce for a single shot and two ounces for a doppio or double shot.

Most espresso cups fall between 60ml and 88ml, although 103ml and 118ml sizes exist.

Turkish coffee is usually served in a ½ demitasse cup that has a slim base with a broad rim to raise the aromas to your palate. 

A wide-rimmed cappuccino cup is typically double the size of an espresso cup and contains liquid 147ml to 177ml. A proper latte cup is shaped like a bowl instead of a mug and contains up to 443ml of brew.

This size lets you add any extra steaming milk or sugar or even create Instagram-worthy art atop your latte.

Some classic oversized latte cups hold 590ml t0 740ml of coffee. It may still hold the typical 6 oz. of coffee, but this size leaves plenty of room for tasty and creamy extras.

Here’s How to Measure a 6 Ounce Cup of Coffee

By now, you know that a standard (imperial) cup of coffee comes out to 177ml that can be poured into an 8 oz. or 12 oz. cup.

While this “golden ratio” results in 6 oz., many people use larger mugs to add milk, cream, or sugar.  

Coffee Cup vs. Coffee Mug Size

A cup of coffee refers to a liquid unit of brewed coffee, while mug size refers to the cup’s capacity. 

While this can be confusing, just remember that no one sips a brimful cup of coffee from a tiny 6 oz. cup. This brewed coffee amount is always poured into a larger mug.

Does a 6 Ounce Cup of Coffee Matter?

Standardization comes into play when you make a cup of coffee. If you used your mug to measure out the water, the results would be very different from mug to mug since not all mugs are a standard size.

It’s important to use a standard measurement to get a good ratio for coffee. Just check out a drip coffee machine to notice that the size mark cup on the coffee maker won’t fill up your mug 6 times.

Instead, it will brew 36 oz. of coffee that would fill a 12-ounce mug only 3 times.

Here’s How to Measure the Right Amount of Coffee

If you want to measure the correct amount of ground coffee to brew a proper 6-ounce cup, you will want to use 2 tablespoons (one scoop of ground coffee) per 6 fl. oz. of water.

Since many coffee scoops aren’t exact, use a 1 tablespoon measuring spoon, smoothed flat, to get the right amount.

Here’s the Coffee-to-Water Ratio to Brew Light, Medium, or Bold Coffee

Keep the ratio right when brewing coffee by using 1 tablespoon of ground coffee per 6 ounces of water if you prefer coffee that’s on the light side. Use 1.5 tablespoon for a medium level brew, and 2 tablespoons for a strong cup of coffee.  

The golden ratio is 1:18 or 1 gram of coffee per 18 grams of water for a perfectly light or medium strength. Try a 1:15 ratio for a bolder brew.

Different Coffee Cup Sizes Around the World

If you’re a coffee connoisseur and a world traveler, you’ve probably already noticed that coffee cup sizes aren’t created equal in every country.

Here are the different coffee cup sizes outside the U.S.

  • America: A “cup of coffee” equals 6 ounces and is often on a much larger scale than other places in the world. In most U. S. coffeeshops, the smallest cup measures 12 oz., but will hold 6 oz. of brewed coffee in addition to milk, cream, syrups, nitrogen, butter, marshmallows, or sugar that add volume depending on the kind of coffee served.
  • Canada: A cup follows the metric standard and contains 250ml. But in a confusing switch, a coffee cup contains 227ml. 
  • Japan: A regular metric cup is 200ml, while the traditional Japanese unit for measure comes in at 180.4ml.
  • Latin America: Coffee cup sizes vary widely from country to country. For example, in Brazil, one cup equals ¾ imperial cup or 177ml, while in Argentina, coffee comes in three sizes: chico (1 shot, typically 1 fl. ounce or 30ml), un jarrito (1.5 shots or 45ml), and a doble (a double shot size or about 60ml).

What Are Common Sizes of Coffee Cups at Popular Coffee Shops?

If you hit up your favorite coffee shop, you’ll find that they all carry different cup sizes that are measured in different milliliters or fluid ounces. 

To avoid confusion and help you pick your perfect coffee cup size, we’ve provided a fast guide to the standard coffee cup sizes at popular coffee shop establishments.


At Starbucks in the States or worldwide, you can choose from 6 recognizable cup sizes in ounces and milliliters based on Italian espresso measurements:

  • Short: 8 fl. oz. or 240 ml
  • Tall: 12 fl. oz. or 350 ml
  • Grande: 16 fl. oz. or 470 ml
  • Venti (Hot): 20 fl. oz. or 590 ml
  • Venti (Cold): 24 fl. oz. or 710 ml
  • Trenta (Cold): 31 fl. oz. or 920 ml

Dutch Bros

Located in 7 western states and Texas, this popular chain has made coffee cup sizes easy with 3 simple options:

  • Small or 12 oz.
  • Medium or 16 oz.
  • Large or 20 oz.


Sprinkled in 338 locations in 182 cities across 20 states, Peets’ coffee cups come in 3 basic sizes:

  • Small: 12 fl. oz or 113 mg.
  • Medium: 16 fl. oz or 150mg.
  • Large: 20 fl. oz. or 187mg.


Whether you grab a solo coffee or add it to a meal, McDonald’s keeps things simple with just four different sizes across its global locations.

  • Small: 8 oz.
  • Medium: 12 oz.
  • Large: 16 oz.
  • Extra Large: 20 oz.

Dunkin’ Donuts

When you roll up to Dunkin’ Donuts for a caffeine kick, you can take your pick from four sizes that range from small up to extra-large.

  • Small: 10 fl. oz. or 296 ml
  • Medium: 14 fl. oz. or 414 ml
  • Large: 20 fl. oz. or 590 ml
  • Extra Large: 24 fl. oz. or 710 ml

Final Thoughts

While coffee cup sizes can seem confusing, a regular cup of coffee in most American coffee shops comes out to 6 brewed ounces.

From Latin America to Europe or Japan, however, these sizes can vary depending on whether the country that you’re visiting uses the imperial or metric measuring system.

Popular U.S. coffee chains such as Starbucks, Dutch Bros, and Dunkin’ Donuts, like many Americans, use the imperial system rather than the metric system.

Keep in mind that everything looks bigger in America, so your 6 oz. coffee may come in an 8 oz. cup unless you request a different size.

While it may come as a surprise that a cup isn’t a standard unit of measurement, follow the standard coffee-to-water ratio to whip up the right proportion at home, or ask a barista about coffee cup sizes and brew amounts if you have any questions next time you order.

Christopher Mize

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