How Many Ounces Are in a Cup? (Liquid vs. Dry Explained)

Here’s the simple answer: 1 cup equals 8 fluid ounces in the US system. But if you’re here, you probably already know it’s not quite that simple. The UK uses different measurements. Dry ingredients have different weights. And your grandmother’s recipe from 1975 doesn’t specify which type of cup she meant.

Let’s clear up the confusion once and for all.

Cup to Ounces Converter

Use the converter tool above to quickly convert between any of these units – it handles US Standard, UK Imperial, and Metric systems.

The Quick Reference Table

Before we get into the details, here’s what you actually came for:

Bookmark this table. You’ll need it more often than you think.

Why This Gets Confusing

The confusion around cups and ounces comes from three main issues:

Issue 1: Volume vs. Weight

Fluid ounces measure volume (how much space something takes up). Dry ounces measure weight (how heavy something is). A cup of feathers and a cup of lead both take up the same space, but they definitely don’t weigh the same.

When a recipe says “8 ounces of flour,” it means weight. When it says “8 fluid ounces of milk,” it means volume. Most recipes assume you know which one they mean. Most of us don’t.

Issue 2: Different Countries, Different Cups

The US, UK, and metric systems all define “cup” differently:

• US cup: 8 fluid ounces (236.59 ml)
• UK cup: 10 fluid ounces (284.13 ml)
• Metric cup: 250 ml (used in Australia, Canada, New Zealand)

This is why your British friend’s recipe never quite works when you try it. You’re literally using different measurements.

Issue 3: Dry Ingredients Vary in Weight

One cup of flour weighs about 4.25 ounces. One cup of sugar weighs about 7 ounces. One cup of butter weighs 8 ounces. Same volume, completely different weights.

This is where things get tricky, and why serious bakers use kitchen scales instead of measuring cups.

Converting Cups to Fluid Ounces

For liquids, the conversion is straightforward:

US System:

• Multiply cups by 8 to get fluid ounces
• Divide fluid ounces by 8 to get cups

Examples:

• 3 cups × 8 = 24 fluid ounces
• 12 fluid ounces ÷ 8 = 1.5 cups

UK System:

• Multiply cups by 10 to get fluid ounces
• Divide fluid ounces by 10 to get cups

Examples:

• 3 cups × 10 = 30 fluid ounces
• 20 fluid ounces ÷ 10 = 2 cups

If you’re working with an international recipe, check which system it uses. Usually, if measurements seem odd (like 10 fluid ounces instead of 8), it’s probably UK.

Common Dry Ingredients: Weight Per Cup

Here’s where you need to pay attention. These are approximate weights for common ingredients:

Flours:

• All-purpose flour: 4.25 oz per cup
• Bread flour: 4.5 oz per cup
• Cake flour: 4 oz per cup
• Whole wheat flour: 4.25 oz per cup

Sugars:

• Granulated white sugar: 7 oz per cup
• Brown sugar (packed): 7.5 oz per cup
• Powdered sugar: 4 oz per cup

Fats:

• Butter: 8 oz per cup (exactly 2 sticks)
• Oil: 7.5 oz per cup
• Shortening: 6.75 oz per cup

Other Common Ingredients:

• Rice (uncooked): 6.5 oz per cup
• Oats (rolled): 3.5 oz per cup
• Chocolate chips: 6 oz per cup
• Nuts (chopped): 4-5 oz per cup

Notice how different these are? This is why baking by weight is more accurate than baking by volume.

How to Measure Correctly

The tool matters as much as the measurement.

For Liquids:

Use a clear measuring cup with markings on the side. Place it on a flat, level surface. Pour in your liquid, then bend down so your eyes are level with the measurement line. Looking from above gives you an inaccurate reading.

For Dry Ingredients:

Use dry measuring cups (the kind that come in sets of 1/4, 1/3, 1/2, and 1 cup). Fill the cup completely, then level off the top with a straight edge like a knife or spatula. Don’t tap the cup or pack it down (unless the recipe specifically says “packed,” like with brown sugar).

For Flour Specifically:

Flour compacts over time. If you scoop directly from the bag, you’ll get more flour than intended. Instead:

1. Fluff up the flour in the container with a spoon
2. Spoon it into your measuring cup
3. Level it off with a straight edge

This method gives you about 4.25 ounces per cup instead of 5+ ounces if you scoop directly.

When to Use Weight Instead of Volume

Professional bakers and serious home bakers measure by weight, not volume. Here’s why you might want to as well:

Baking Bread: Ratios of flour to water are critical. Weight measurements are far more consistent.

Making Pastries: Precise ratios of butter to flour make the difference between flaky and tough pastry.

Scaling Recipes: Doubling a recipe measured by weight is simple. Doubling volume measurements can compound small errors.

Following Professional Recipes: Many good recipes list weights because it’s more accurate.

A basic kitchen scale costs $15-20 and removes all the guesswork. You just put your bowl on the scale, zero it out, and add ingredients until you hit the right weight.

Common Measurement Mistakes

Using Dry Cups for Liquids (or Vice Versa)

Dry measuring cups don’t let you measure exactly to the line – they’re meant to be filled completely and leveled. Liquid measuring cups have space above the measurement line to prevent spilling. Using the wrong type can throw off your measurements by 10-20%.

Not Leveling Dry Ingredients

A heaping cup of flour can contain 6+ ounces instead of 4.25 ounces. That’s 50% more flour than the recipe calls for. Your cookies will be dry, your cakes will be dense.

Packing Flour

Unless a recipe specifically says “packed,” don’t pack flour down. Scooping directly from the bag packs it naturally. Always fluff and spoon flour instead.

Confusing Fluid Ounces with Weight Ounces

8 fluid ounces of water weighs about 8 ounces. But 8 fluid ounces of honey weighs about 12 ounces. They’re different measurements for different things.

Measuring Sticky Ingredients in Dry Cups

Honey, molasses, peanut butter – these are technically “dry” ingredients but they’re impossible to level in a dry measuring cup. Use liquid measuring cups and lightly oil them first so the ingredient slides out cleanly.

Quick Conversions You’ll Actually Use

The converter at the top of this page handles all these conversions automatically, including cups, fluid ounces, tablespoons, teaspoons, milliliters, and liters. But if you want to memorize the most common ones:

Cups to Tablespoons:

• 1 cup = 16 tablespoons
• 1/2 cup = 8 tablespoons
• 1/4 cup = 4 tablespoons

Cups to Teaspoons:

• 1 cup = 48 teaspoons
• 1/2 cup = 24 teaspoons
• 1/4 cup = 12 teaspoons

Sticks of Butter to Cups:

• 1 stick = 1/2 cup = 4 oz
• 2 sticks = 1 cup = 8 oz

Liquid Volume Equivalents:

• 1 cup = 8 fl oz = 237 ml
• 1 pint = 2 cups = 16 fl oz
• 1 quart = 4 cups = 32 fl oz
• 1 gallon = 16 cups = 128 fl oz

Adjusting International Recipes

If you’re following a recipe from another country, here’s how to adjust:

UK to US Conversion:

• Multiply UK cups by 1.25 to get US cups
• Example: 2 UK cups = 2.5 US cups

Metric to US Conversion:

• Divide milliliters by 237 to get US cups
• Example: 500 ml ÷ 237 = about 2.1 US cups

US to Metric:

• Multiply US cups by 237 to get milliliters
• Example: 1.5 cups × 237 = about 355 ml

The easiest solution? Find the recipe rewritten for your measurement system. Most popular recipes have versions for different regions.

FAQs

Can I use a regular drinking glass as a measuring cup?

No. Drinking glasses aren’t standardized. What you think is “about a cup” might be 6 ounces or 12 ounces. Buy actual measuring cups – they’re cheap and accurate.

Do I need both liquid and dry measuring cups?

Yes, if you want accurate results. You can get away with using liquid cups for everything, but dry cups for liquids will always be slightly off.

How many ounces in half a cup?

4 fluid ounces in the US system, 5 fluid ounces in the UK system.

How many ounces in a quarter cup?

2 fluid ounces in the US system, 2.5 fluid ounces in the UK system.

Why do some recipes use weight and others use volume?

Volume measurements (cups) are traditional in American home cooking. Weight measurements (ounces/grams) are standard in professional baking and in most other countries. Weight is more accurate, but volume is more convenient for casual cooking.

Does it really matter if I’m off by a little bit?

For cooking (soups, stews, sauces), small variations usually don’t matter. For baking (cakes, cookies, bread), accuracy matters a lot. Baking is chemistry – the ratios of ingredients determine whether your cake rises properly or your cookies spread correctly.

What if a recipe lists cups and my scale only shows grams?

Use these conversions:

• 1 cup flour = 120 grams
• 1 cup sugar = 200 grams
• 1 cup butter = 227 grams
• 1 cup liquid = 237 grams (for water-based liquids)

The Bottom Line

For liquids, the conversion is simple: 1 US cup equals 8 fluid ounces. For dry ingredients, weight per cup varies dramatically depending on what you’re measuring.

If you’re just making soup or a sauce, measuring cups work fine and small variations don’t matter. If you’re baking something where texture and rise matter, consider investing in a kitchen scale and measuring by weight instead.

Either way, now you know exactly how many ounces are in a cup – and more importantly, why it’s not always as simple as it seems.