Cups to Ounces Converter
Convert US cups to fluid ounces for cooking, baking, and beverage measurement.
How It Works
Formula: US cup to fl oz = value × 8
Example: 1 US cup = 8 fl oz
Note: 1 US cup equals 8 fluid ounces, the standard volume relationship in American recipes.
Common Uses
Quick Conversion Table
| US cup | fl oz |
|---|---|
| 0.5 | 4 |
| 1 | 8 |
| 2 | 16 |
| 4 | 32 |
| 8 | 64 |
| 16 | 128 |
| 32 | 256 |
| 64 | 512 |
Rounding Rule
Rounded to 2 decimal places
Error Margin
±0.01 fl oz
Precision Guidance
For cooking, round to 1 decimal. For mixology, keep 2 decimals.
Common Mistakes
Fluid ounces measure volume; weight ounces differ. Do not swap them when a recipe gives weights.
Frequently Asked Questions
What is 1 cup in fluid ounces?
1 US cup equals 8 fluid ounces (1 cup = 8 fl oz = 236.59 mL).
How do I convert cups to ounces?
Multiply the cup value by 8. For example, 1.5 cups × 8 = 12 fl oz.
Is this fluid ounces or weight ounces?
This converts to fluid ounces (volume), not avoirdupois ounces (weight). They differ for most ingredients.
How many cups in 16 oz?
16 fl oz equals 2 US cups.
Deep Dive Guide
Cups to Ounces: US Liquid Conversion for Cooking and Baking
Convert cups to fluid ounces accurately for US recipes, cooking, and liquid measurements. 1 cup equals 8 fluid ounces.
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Exact Constants & Authoritative Sources
Every conversion on this page uses the fixed, internationally agreed constants below — drawn from NIST and the SI Brochure. No values are estimated or rounded as if exact. See the full list on our Sources & Standards page.
- EXACT1 US gallon (gal) = 3.785411784 litres (exact, 231 in³)
- EXACT1 US fluid ounce (fl oz) = 29.5735295625 mL (exact, 1/128 gal)
- EXACT1 US cup = 236.5882365 mL (exact, 8 fl oz)
- EXACT1 US pint (pt) = 473.176473 mL (exact, 16 fl oz)
- EXACT1 US quart (qt) = 946.352946 mL (exact, 32 fl oz)
- EXACT1 litre (L) = 1000 millilitres (definition)
Common Pitfalls & How to Avoid Them
US vs. Imperial (UK) cups
A US cup is 236.59 mL, but a UK/metric cup is 250 mL and an Imperial cup is ~284 mL. Recipes from different countries are not interchangeable drop-in.
Fluid ounce is volume, not mass
A US fl oz is 29.57 mL of volume. 1 fl oz of water ≈ 29.57 g, but 1 fl oz of honey or oil weighs more. Do not treat fluid ounces as grams.
Teaspoon/tablespoon sizes differ
1 US tbsp = 14.7868 mL; 1 US tsp = 4.92892 mL. Metric measuring spoons are 15 mL and 5 mL — close but not exact; for baking precision use weighed grams.
A unit-conversion reference site has no manufacturer-specific or device calibration parameters, so "layered tuning" does not apply here. The only real error-handling is input validation: the converter rejects non-numeric, empty, or out-of-range entries and shows a clear message, then falls back to exact constants above. No estimated or rounded figures are ever presented as exact.
Authoritative sources for this page
- NIST (U.S. National Institute of Standards and Technology) — NIST SP 330 — The International System of Units (SI), 2019 edition
- BIPM (International Bureau of Weights and Measures) — SI Brochure — The International System of Units (9th edition)
Last Updated 2026 | This converter was reviewed for accuracy