Cup (cup) - Unit Information & Conversion

Quick Answer

What is a Cup? A cup is a volume measurement used in cooking and baking.

The Three Main Types:

• US Customary Cup: 236.59 mL (8 fluid ounces) - Used in the United States
• Metric Cup: 250 mL - Used in Australia, New Zealand, Canada
• Imperial Cup: 284 mL (10 fluid ounces) - Historical UK measurement (rarely used today)

Quick Conversions (US Cup):

• 1 cup = 16 tablespoons
• 1 cup = 48 teaspoons
• 1 cup = 8 fluid ounces
• 1 cup = 236.59 milliliters

Quick Comparison Table

Cups	Tablespoons	Fluid Ounces	Milliliters	Common Use
1/4 cup	4 tbsp	2 fl oz	59 mL	Butter, oil
1/3 cup	5⅓ tbsp	2.7 fl oz	79 mL	Liquids, sugar
1/2 cup	8 tbsp	4 fl oz	118 mL	Milk, water
2/3 cup	10⅔ tbsp	5.3 fl oz	158 mL	Rice, flour
3/4 cup	12 tbsp	6 fl oz	177 mL	Sugar, flour
1 cup	16 tbsp	8 fl oz	237 mL	Standard measure
2 cups	32 tbsp	16 fl oz	473 mL	1 pint
4 cups	64 tbsp	32 fl oz	946 mL	1 quart

Definition

The US Customary Cup

1 US Cup = 236.588237 milliliters (exactly)

This is defined as exactly 8 US fluid ounces.

Breakdown:

• 1 cup = 8 fluid ounces
• 1 cup = 16 tablespoons
• 1 cup = 48 teaspoons
• 1 cup = 1/2 pint
• 1 cup = 1/4 quart
• 1 cup = 1/16 gallon

The Metric Cup

1 Metric Cup = 250 milliliters (exactly)

Used in Australia, New Zealand, and Canada for recipes.

Why 250 mL?

• Nice round number in the metric system.
• Close to the US cup (only 5.7% larger).
• Easy to work with (1/4 liter).

The Imperial Cup

1 Imperial Cup = 284.131 milliliters

Based on the imperial fluid ounce (10 imperial fl oz).

• Rarely used today (UK now uses metric).
• 20% larger than a US cup.

Dry vs. Liquid Cups

Important Distinction:

Liquid Measuring Cups:

• Have a spout for pouring.
• Marked below the rim (to prevent spilling).
• Measured by filling to the line.

Dry Measuring Cups:

• Flat rim (for leveling).
• Filled to the brim and leveled with a knife.
• More accurate for flour, sugar, etc.

Volume is the same (8 fl oz), but the measuring technique differs.

History: From Teacups to Standardization

Before 1896: Chaos in the Kitchen

Before standardization, recipes were vague:

• "A teacup of flour" (but teacups varied in size!)
• "A coffee cup of sugar" (different from a teacup!)
• "A wine glass of milk" (which size glass?)

This led to inconsistent results. The same recipe could turn out differently every time.

Fannie Farmer's Revolution (1896)

Fannie Merritt Farmer, director of the Boston Cooking School, published the "Boston Cooking-School Cook Book" in 1896.

Her Innovation:

• Standardized the cup to exactly 8 fluid ounces.
• Introduced level measurements (level off with a knife).
• Specified exact amounts (1 cup, 1/2 cup, 1/4 cup).

Impact:

• Recipes became reproducible.
• Home cooks could follow recipes with confidence.
• The cup became the standard in American cooking.

The Metric Cup (1970s)

When Australia, New Zealand, and Canada adopted the metric system, they created the metric cup (250 mL).

Why not use the US cup?

• 236.59 mL is an awkward number in metric.
• 250 mL is a round number (1/4 liter).

Result:

• US recipes use 236.59 mL cups.
• Australian/NZ recipes use 250 mL cups.
• Confusion when converting between systems!

Real-World Examples

Common Ingredients by Cup

Ingredient	Weight per Cup (US)	Notes
Water	236 g	1 mL = 1 g
All-Purpose Flour	120-125 g	Depends on packing
Granulated Sugar	200 g	Packed
Brown Sugar (Packed)	220 g	Firmly packed
Butter	227 g	2 sticks
Vegetable Oil	218 g	Lighter than water
Milk	244 g	Slightly heavier than water
Honey	340 g	Very dense
Rice (Uncooked)	185 g	Long grain
Oats (Rolled)	90 g	Light and fluffy
Cocoa Powder	85 g	Sifted
Powdered Sugar	120 g	Sifted

Key Insight: 1 cup ≠ 1 cup in weight! Volume is constant, but weight varies by ingredient density.

Baking Ratios (Baker's Percentages)

Professional bakers use weight, not volume, because it's more accurate.

Example: Basic Bread

• Flour: 3 cups (360 g) - 100%
• Water: 1.5 cups (360 mL) - 60%
• Yeast: 2 tsp (7 g) - 2%
• Salt: 1.5 tsp (9 g) - 2.5%

Why Weight Matters:

• Flour packing: 1 cup can weigh 120-150 g depending on how it's scooped.
• Humidity: Flour absorbs moisture, changing weight.
• Consistency: Weight ensures the same result every time.

Common Uses

1. Baking

The cup is essential for American baking recipes.

Standard Measurements:

• Flour: 1-3 cups (depending on recipe)
• Sugar: 1/2 - 2 cups
• Butter: 1/2 - 1 cup (1-2 sticks)
• Milk: 1/2 - 1 cup

Precision Matters:

• Too much flour: Dry, dense baked goods.
• Too little flour: Flat, soggy results.
• Solution: Spoon flour into cup, level off (don't scoop and pack).

2. Cooking

Liquids:

• Water, broth, milk: Easy to measure in cups.
• Oil: 1/4 - 1/2 cup for sautéing.

Grains:

• Rice: 1 cup uncooked = 3 cups cooked.
• Pasta: 2 cups uncooked = 4 cups cooked.

Vegetables:

• Chopped vegetables: 1-2 cups (onions, peppers, etc.).

3. Nutrition & Serving Sizes

USDA Serving Sizes:

• Cooked Rice: 1 cup = 1 serving.
• Pasta: 1 cup cooked = 1 serving.
• Vegetables: 1 cup raw = 1 serving.
• Milk: 1 cup = 1 serving (8 oz).
• Cereal: 1 cup = 1 serving (varies by type).

4. Coffee & Beverages

Coffee Brewing:

• Standard Ratio: 1-2 tablespoons coffee per 1 cup (6 oz) water.
• Note: A "cup" of coffee is often 6 oz, not 8 oz!

Tea:

• 1 cup water (8 oz) per tea bag.

Conversion Guide

Cups to Tablespoons

Formula: $$ \text{Tablespoons} = \text{Cups} \times 16 $$

Cups	Tablespoons
1/8 cup	2 tbsp
1/4 cup	4 tbsp
1/3 cup	5⅓ tbsp
1/2 cup	8 tbsp
2/3 cup	10⅔ tbsp
3/4 cup	12 tbsp
1 cup	16 tbsp

Cups to Milliliters

US Cup: $$ \text{mL} = \text{Cups} \times 236.59 $$

Metric Cup: $$ \text{mL} = \text{Cups} \times 250 $$

US Cups	mL (US)	mL (Metric)
1/4	59 mL	62.5 mL
1/2	118 mL	125 mL
1	237 mL	250 mL
2	473 mL	500 mL
4	946 mL	1,000 mL (1 L)

Cups to Fluid Ounces

Formula: $$ \text{Fluid Ounces} = \text{Cups} \times 8 $$

Cups	Fluid Ounces
1/4	2 fl oz
1/2	4 fl oz
1	8 fl oz
2	16 fl oz (1 pint)
4	32 fl oz (1 quart)

Common Conversion Mistakes

Mistake #1: Using the Wrong Cup Type

Wrong: Using a metric cup (250 mL) for a US recipe. Right: Use a US cup (237 mL) or convert the recipe. Impact: 5.7% more of every ingredient (can affect texture).

Mistake #2: Scooping Flour

Wrong: Scooping flour directly from the bag. Right: Spoon flour into cup, level off. Impact: 25-30% more flour = dry, dense results.

Mistake #3: Packing Brown Sugar Incorrectly

Wrong: Loosely filling the cup. Right: Pack firmly until it holds its shape when turned out. Impact: Too little sugar = less sweetness, different texture.

Mistake #4: Confusing Fluid Ounces with Weight Ounces

Fluid Ounces (fl oz): Volume measurement. Ounces (oz): Weight measurement.

Example:

• 1 cup water = 8 fl oz (volume) = 8.3 oz (weight).
• 1 cup flour = 8 fl oz (volume) = 4.4 oz (weight).

They're only equal for water!

Fun Facts About Cups

• Fannie Farmer's Legacy: Her 1896 cookbook sold over 4 million copies and is still in print today.
• The "Legal" Cup: The US FDA defines a "legal cup" as exactly 240 mL for nutrition labeling (different from the customary cup!).
• Coffee Cup Confusion: A "cup" of coffee is often 6 oz, not 8 oz. Coffee makers use this smaller measure.
• Butter Sticks: In the US, 1 stick of butter = 1/2 cup = 8 tablespoons. The wrapper has markings for tablespoons!
• The Metric Holdout: The US is one of only three countries (with Liberia and Myanmar) that hasn't fully adopted the metric system.

Comprehensive Conversion Table

Cups	Tablespoons	Teaspoons	Fluid Ounces	Milliliters	Liters
1/8	2	6	1	30	0.03
1/4	4	12	2	59	0.06
1/3	5⅓	16	2.7	79	0.08
1/2	8	24	4	118	0.12
2/3	10⅔	32	5.3	158	0.16
3/4	12	36	6	177	0.18
1	16	48	8	237	0.24
2	32	96	16	473	0.47
4	64	192	32	946	0.95
8	128	384	64	1,893	1.89
16	256	768	128	3,785	3.79

Glossary of Cooking Measurements

• Cup: Volume unit = 8 fluid ounces (US) or 250 mL (metric).
• Tablespoon (tbsp): 1/16 cup = 15 mL.
• Teaspoon (tsp): 1/48 cup = 5 mL.
• Fluid Ounce (fl oz): Volume measurement (not weight).
• Ounce (oz): Weight measurement (not volume).
• Pint: 2 cups = 16 fl oz.
• Quart: 4 cups = 32 fl oz.
• Gallon: 16 cups = 128 fl oz.
• Liter: 4.23 cups (US) or 4 cups (metric).
• Milliliter (mL): 1/1000 of a liter.
• Gram (g): Weight measurement (metric).
• Pound (lb): Weight measurement = 16 ounces.
• Stick (Butter): 1/2 cup = 8 tablespoons = 113 g.

Kitchen Tips for Accurate Measuring

Liquid Ingredients

Best Practices:

1. Use a liquid measuring cup (with spout and markings).
2. Place on level surface (don't hold in hand).
3. Check at eye level (bend down to see the meniscus).
4. Pour slowly near the target line.

Common Mistakes:

• Holding cup in air (uneven surface).
• Looking from above (parallax error).
• Overfilling (surface tension creates dome).

Dry Ingredients

Best Practices:

1. Use dry measuring cups (flat rim for leveling).
2. Spoon ingredient into cup (don't scoop).
3. Level off with straight edge (knife, spatula).
4. Don't tap or shake (compacts ingredient).

Flour-Specific:

• Fluff flour in container first.
• Spoon into cup (never scoop).
• Level with knife.
• Result: 120-125 g per cup (correct).

Brown Sugar-Specific:

• Pack firmly into cup.
• Should hold shape when turned out.
• Result: 220 g per cup (packed).

Sticky Ingredients (Honey, Peanut Butter)

Pro Tips:

1. Spray cup with cooking spray first (easier release).
2. Use rubber spatula to scrape out completely.
3. Weigh instead if possible (more accurate).

Alternative:

• Honey: 1 cup = 340 g (weigh for precision).
• Peanut Butter: 1 cup = 250 g.

Temperature Matters

Butter:

• Melted: Measure as liquid.
• Softened: Pack into dry cup, level off.
• Cold: Cut into tablespoon marks on wrapper.

Liquids:

• Cold vs. Hot: Volume changes slightly with temperature.
• Best Practice: Measure at room temperature.

Recipe Scaling Guide

Doubling a Recipe

Simple Multiplication:

• 1 cup → 2 cups
• 1/2 cup → 1 cup
• 1/4 cup → 1/2 cup

Watch Out For:

• Leavening agents (baking powder, baking soda): Don't always double perfectly.
• Spices: Taste may be too strong if doubled exactly.
• Baking time: May need 1.5x time, not 2x.

Halving a Recipe

Division:

• 1 cup → 1/2 cup
• 1/2 cup → 1/4 cup
• 1/4 cup → 2 tablespoons

Tricky Measurements:

• 1/3 cup ÷ 2 = 2 tablespoons + 2 teaspoons
• 3/4 cup ÷ 2 = 6 tablespoons (or 1/4 cup + 2 tbsp)

Converting to Metric (Weight)

Why Weight is Better:

• More accurate (no packing variability).
• Easier to scale (multiply/divide by any number).
• Professional standard (all bakeries use weight).

Common Conversions:

• 1 cup flour = 120 g
• 1 cup sugar = 200 g
• 1 cup butter = 227 g
• 1 cup water = 237 g

Invest in a Kitchen Scale:

• Cost: $10-30
• Benefit: Perfect results every time
• Bonus: Less cleanup (weigh directly into bowl)

Grand Technical Cup Registry: Part 5