1 Ounce to mL
Exactly how many milliliters are in 1 fluid ounce? 1 US fl oz = 29.5735 mL, with a quick reference table for common bottle sizes.
1 Ounce to mL: The Quick Answer
1 fluid ounce (1 fl oz) converts to 29.57 mL. Whether you are reading a metric label, a recipe, or an international spec, knowing how to convert 1 fluid ounce (1 fl oz) keeps your numbers consistent. Use our fl oz to ml converter for any value, or read on for the full breakdown of the 29.57 mL result.
The Exact Fluid Ounces to Milliliters Formula
The US fluid ounce is defined as exactly 1/128 of a US gallon, which works out to 29.5735 mL. To convert fluid ounces to milliliters, multiply the ounces by 29.5735.
Step-by-Step Calculation
Start with 1 fl oz. Multiply by 29.5735: 1 x 29.5735 = 29.5735 mL, which rounds to 29.57 mL.
A Quick Mental Estimate
A fluid ounce is just under 30 mL, so rounding to 30 mL is a handy estimate that is only about 0.4 mL low.
Where 1 fluid ounce (1 fl oz) Comes Up
Fluid ounces show up on US drink bottles, canned goods, and perfume sizes, while the rest of the world uses milliliters. One fluid ounce of water, juice, or lotion is 29.57 mL, the link you need to read a metric label or fill a metric measure.
1 fluid ounce (1 fl oz) Compared With Nearby Values
Common fluid-ounce amounts: 0.5 fl oz = 14.79 mL, 2 fl oz = 59.15 mL.
On the other side, 8 fl oz = 236.59 mL, 16 fl oz = 473.18 mL. Each step moves the figure smoothly, so the same formula scales to any amount.
Practical Uses of the 1 fluid ounce (1 fl oz) Conversion
Use it when comparing a US bottle to a metric one, scaling a cocktail, or reading a cosmetics label in mL. Our fluid ounces to mL converter converts any amount, and mL to cups moves between mL and cups.
Frequently Asked Questions
How many mL is 1 fluid ounce?
1 US fl oz = 29.5735 mL (about 29.57 mL).
How many mL is 8 oz?
8 fl oz × 29.5735 = 236.588 mL (1 cup).
Is a US fl oz the same as a UK fl oz?
No. A UK fl oz is 28.413 mL; the US fl oz is 29.5735 mL.
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Quick Summary
1 fluid ounce (1 fl oz) equals 29.57 mL. Use the fluid ounces to milliliters relationship shown above for exact, repeatable results.
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Fluid Ounces to mL: Convert US Liquid Volume to Metric
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Gallons to Liters: Convert US Volume to Metric Units
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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.
16 oz to mL: Convert a US Pint to Metric Volume
Convert 16 oz to mL with the exact US formula. 16 fluid ounces equals 473.18 mL, the size of one US pint. See the math, uses, and 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