Convert Cup to Fluid Ounce (cup → fl oz)

Converting cups to fluid ounces is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in cups

   Start with the number of cups (cup) you want to convert.
2. 2
   Multiply by 8.115365

   The conversion factor from cup to fl oz is 8.115365. Multiply your value by this number.
3. 3
   Read the result in fluid ounces

   The result is your value in fluid ounces (fl oz).

Multiply the value in cups by 8.115365. For the reverse direction, multiply by 0.123223.

• ✓US cup = 240 ml common; 236.6 ml legal; UK cup = 284 ml; metric cup (AU/NZ) = 250 ml.
• ✓Weights (grams) are more reliable than cups — a cup of flour can vary 30% depending on how packed.
• ✓For baking, always use the recipe author's country convention.

• ✗Using a UK 284 ml cup for a US recipe calling for 240 ml — 18% overshoot.
• ✗Treating all dry ingredients as 1 cup = 240 g — only true for water.
• ✗Using a coffee mug as a "cup" — mugs vary 200–400 ml.

What is the Cup?

The US cup equals exactly 240 milliliters (a definition standardized for nutrition labeling; the legal volume for cooking is 236.588 mL, derived from 8 US fluid ounces). The cup is the cornerstone of American baking and home cooking, with virtually every US recipe using volume measurements rather than the weight measurements common in European cooking. Standard measuring-cup sets include 1, ½, ⅓, and ¼ cup sizes. The metric cup (used in Australia, New Zealand, and increasingly in international recipes) is exactly 250 mL — slightly larger than the US cup. The cup relates to the gallon (16 cups = 1 gal), the pint (2 cups = 1 pt), the fluid ounce (8 fl oz = 1 cup), the tablespoon (16 tbsp = 1 cup), and the milliliter (1 cup ≈ 237–240 mL). American baking-by-volume is sometimes criticized internationally for its variability compared to gram-based measurements.

• US cooking and baking recipes
• Cereal and beverage serving sizes in US nutrition labels
• Volume estimation when no scale is available

What is the Fluid Ounce?

The US fluid ounce equals exactly 29.5735295625 milliliters and is the standard small-volume unit for beverages, cocktails, personal-care products, and cooking in the United States. It is distinct from the (weight) ounce: 1 fluid ounce of water weighs about 1 ounce by weight at room temperature, but other liquids may weigh more or less. Soft-drink cans (12 fl oz), beer bottles (12 fl oz), shampoo bottles, and skin-cream tubs all label volume in fluid ounces. The US fluid ounce is slightly different from the UK imperial fluid ounce (28.4131 mL — about 4% smaller), reflecting the different gallon definitions. The US fl oz relates to the gallon (128 fl oz = 1 gal), the cup (8 fl oz = 1 cup), the tablespoon (2 tbsp = 1 fl oz), and the milliliter (1 fl oz ≈ 29.57 mL). Cocktail recipes universally use fluid ounces.

• US beverage and soda can sizes (12 fl oz)
• Cosmetic and personal-care product volumes
• US fluid recipes and cocktail measures