oz to ml: Convert Fluid Ounces to Milliliters
Convert oz to ml: one US fluid ounce equals 29.57 ml. Learn the exact factor, how it is used in recipes and bottle sizes, and common fluid-ounce-to-ml values.
Why Fluid Ounces to ml Comes Up
The fluid ounce measures volume in US recipes, drink bottles, and cosmetic labels, while milliliters are the metric standard worldwide. Converting oz to ml is a daily task in cooking and shopping.
One US fluid ounce equals 29.5735295625 ml. Our fl oz to ml converter gives the precise value; 29.57 ml is the usual rounded figure.
The oz to ml Formula
The US fluid ounce is defined as exactly 29.5735295625 ml (one eighth of a US cup, since a cup is 236.588 ml). Multiply fluid ounces by 29.5735295625 to get milliliters.
The Exact Calculation
For 1 fl oz: 1 × 29.5735295625 = 29.5735 ml, rounded to 29.57 ml. For 8 fl oz: 8 × 29.5735 = 236.59 ml, which is exactly one US cup.
Be careful to use fluid ounces (volume), not weight ounces. A fluid ounce of water weighs about 29.57 g, but the ml conversion is about volume regardless of substance.
US vs UK Fluid Ounce
The US fluid ounce is the larger of the two: 29.5735 ml. The imperial (UK) fluid ounce is slightly smaller at 28.4131 ml. For US recipes, bottles, and labels, use 29.57 ml.
What the Numbers Look Like
Bottle and can sizes make the scale familiar. A 1 fl oz shot is 29.57 ml; a 2 fl oz (60 ml) travel bottle; a 16.9 fl oz water bottle is about 500 ml; a 32 fl oz (1 quart) bottle is about 946 ml.
On a recipe, 4 fl oz is about 118 ml and 8 fl oz (1 cup) is 237 ml. Our guide to 8 oz to ml covers the cup-sized case in detail.
oz to ml Compared With Nearby Volumes
Reference points: 0.5 fl oz = 14.79 ml, 2 fl oz = 59.15 ml, 10 fl oz = 295.74 ml. Each fluid ounce adds 29.57 ml, so amounts scale smoothly.
For the reverse, converting ml back to fl oz divides by 29.57, useful when a metric bottle size needs a US label.
When You Need oz in ml
The conversion is key for recipes and product labels. A US recipe calling for 6 fl oz of liquid becomes about 177 ml on a metric measuring cup. Cosmetic and medicine doses listed in fl oz map to the ml markings on syringes and cups.
It also helps when comparing bottle sizes while shopping abroad, since most of the world prints milliliters.
Frequently Asked Questions
How many ml is 1 oz?
1 US fluid ounce equals 29.5735 ml, normally rounded to 29.57 ml.
How do I convert oz to ml?
Multiply fluid ounces by 29.5735295625. For 8 fl oz: 8 × 29.5735 = 236.59 ml (one cup).
Is a US fl oz the same as a UK fl oz?
No. The US fl oz is 29.57 ml; the UK (imperial) fl oz is about 28.41 ml. Use 29.57 ml for US recipes.
How many ml is 16 oz?
16 US fl oz equals 473.18 ml, which is one US pint.
Does oz mean weight or volume here?
Here it means fluid ounce (volume). Weight ounces convert to grams, not ml.
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Quick Summary
1 US fluid ounce equals 29.57 ml. Multiply fl oz by 29.5735295625: 1 × 29.5735 = 29.57 ml. Eight fl oz is exactly one US cup (236.59 ml).
Related Guide
8 oz to mL: What a Standard US Cup Really Holds
Convert 8 oz to mL with the exact US formula. 8 fluid ounces equals 236.59 mL, the size of one US cup. See the math, uses, and common comparisons.
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Disclaimer
Unit conversions on this site use internationally recognized, fixed conversion factors (for example, 1 inch = 2.54 cm, 1 pound = 0.45359237 kg, 1 °F = (°C × 9/5) + 32). They are provided for general, informational, and educational use. For applications where accuracy is critical — such as medical dosing, engineering, scientific research, trade, or legal compliance — always verify results against authoritative sources such as the U.S. National Institute of Standards and Technology (NIST) and the official International System of Units (SI) brochure, and follow any applicable local standards.
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 article was reviewed for accuracy