Cups to Fluid Ounces Calculator
Instantly convert US cups to fluid ounces and other common cooking volume units. Enter any number of cups — including fractions — and get the exact fl oz result plus tablespoons, teaspoons, pints, quarts, and metric equivalents.
cup
1 US cup = 8 US fluid ounces (exact)
- 1
Fluid ounces per cup
81 US cup = 8 US fluid ounces exactly - 2
Fluid ounces = cups × 8
2 × 8 = 16
How does this calculator work?
Multiply cups by 8 to get US fluid ounces. One cup equals 8 fl oz, 16 tablespoons, 48 teaspoons, ½ pint, ¼ quart, and about 236.6 mL. The ratio is exact by US definition, so there is no rounding error for whole-cup conversions.
Formula
How this is calculated
The US cup is defined as exactly 8 US fluid ounces, or approximately 236.588 millilitres. This is an exact integer ratio, so the conversion is a straight multiplication: fluid ounces = cups × 8. All other cooking-unit conversions flow from the same definition: 1 cup holds 16 tablespoons (each tablespoon = ½ fl oz), 48 teaspoons (each teaspoon = ⅙ fl oz), ½ US pint, and ¼ US quart.
These are US customary units, not Imperial (UK) measures. The Imperial fluid ounce is slightly smaller (≈ 28.41 mL) compared to the US fluid ounce (≈ 29.57 mL), and the Imperial cup (used in Canada and the UK) equals 10 Imperial fluid ounces rather than 8. For recipes from different countries, always check which cup system is intended.
The converter works equally well for whole numbers and fractions such as ⅓ cup (≈ 2.67 fl oz) or ¾ cup (6 fl oz). Typing a decimal like 0.333 for ⅓ cup gives an accurate result without needing a fraction.
Frequently asked questions
There are exactly 8 US fluid ounces in 1 US cup. This ratio is exact by definition, so 2 cups = 16 fl oz, ½ cup = 4 fl oz, and ¼ cup = 2 fl oz.
No. A US cup is 8 US fluid ounces (≈ 236.6 mL). A UK/Imperial cup is 10 Imperial fluid ounces (≈ 284.1 mL) — about 20 % larger. Modern British recipes mostly use grams rather than cups, so always check the source before converting.
One US cup equals 16 US tablespoons. Each tablespoon is ½ fluid ounce, so 16 tablespoons × ½ fl oz = 8 fl oz = 1 cup.
TG we-Calculate Editorial Team. (2026). Cups to Fluid Ounces Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cups-to-oz-calculator
TG we-Calculate Editorial Team. "Cups to Fluid Ounces Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/cups-to-oz-calculator.
TG we-Calculate Editorial Team, "Cups to Fluid Ounces Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cups-to-oz-calculator
@misc{wecalculate_cups_to_oz_calculator, title = {Cups to Fluid Ounces Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cups-to-oz-calculator}}, year = {2026}, note = {TG we-Calculate} }
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