Oz to Ml Converter — Convert Fluid ounces to milliliters
Convert fluid ounces to milliliters with the exact factor, a common-values table, and the formula shown.
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Oz to Ml Converter
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Fluid Ounces to Milliliters — the Quick Answer
One US fluid ounce equals exactly 29.5735295625 ml. For everyday purposes the rounded value 29.5735 mlis more than sufficient — the truncated digits represent a volume smaller than a drop. To convert any volume in US fluid ounces to milliliters, multiply by 29.5735. To go the reverse direction, divide milliliters by 29.5735 (or multiply by 0.033814).
US vs. UK fluid ounce: If you are working with an Imperial (UK) recipe, note that 1 UK fluid ounce = 28.4131 ml, not 29.5735 ml. The difference is about 4%, which is small for a single ounce but accumulates: at 16 fl oz (1 US pint vs. 1 UK pint) the two systems differ by nearly 19 ml — almost four teaspoons. Recipes from British, Australian, and older Commonwealth sources will use the Imperial ounce unless they explicitly state “US fl oz.” This converter uses US fluid ounces throughout.
The Fluid Ounces to Milliliters Formula
US Fluid Ounces → Milliliters
ml = fl oz × 29.5735295625exact inverse: fl oz = ml ÷ 29.5735295625
The factor 29.5735295625 is derived from the defined relationships in the US customary volume system. The US gallon is defined as exactly 231 cubic inches; one cubic inch is exactly 16.387064 ml (since the inch is defined as 25.4 mm exactly); therefore 1 US gallon = 231 × 16.387064 = 3785.41178 ml. Dividing by 128 (the number of fluid ounces in a US gallon) gives 29.5735295625 ml per fl oz. For 8 fl oz (1 cup): 8 × 29.5735 = 236.588 ml.
Source:NIST Handbook 44 — Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices· National Institute of Standards and Technology
The derivation chain is worth knowing because it shows why the US fl oz in milliliters is an irrational-looking decimal: it traces back to the inch (defined as 25.4 mm in 1959) and the gallon (231 in³, defined in the 18th century). Neither of those choices was made with metric compatibility in mind, so the result is a long decimal. The UK Imperial fluid ounce takes a different path: 1 Imperial gallon = 4.54609 liters exactly (by UK statute since 1985), and since there are 160 Imperial fluid ounces in an Imperial gallon, 1 UK fl oz = 4546.09 ÷ 160 = 28.4131 ml.
Common Fluid-Ounce to Milliliter Values
The table below covers the fluid ounce quantities most often encountered in beverages, medicine dosing, and cooking. Values use the 29.5735 ml/fl oz factor, rounded to 1 ml for clarity.
Factor: 1 US fl oz = 29.5735 ml
Common US fluid ounces to milliliters conversions
| Scenario | US Fluid Ounces | Milliliters (ml) | Real-world context |
|---|---|---|---|
| 1 fl oz | 29.6 ml | shot glass / medicine cup | |
| 2 fl oz | 59.1 ml | double shot / small cocktail measure | |
| 4 fl oz | 118.3 ml | ½ cup / standard wine pour (4 oz) | |
| 8 fl ozRecommended | 236.6 ml | 1 US cup / standard glass of water | |
| 12 fl oz | 354.9 ml | standard US soda/beer can | |
| 16 fl oz | 473.2 ml | 1 US pint / large water bottle | |
| 20 fl oz | 591.5 ml | large fountain drink / UK pint (≈568 ml) | |
| 32 fl oz | 946.4 ml | 1 US quart / large sports bottle | |
| 64 fl oz | 1,892.7 ml | ½ US gallon / large juice carton | |
| 128 fl oz | 3,785.4 ml | 1 US gallon |
Note: a 20 fl oz US bottle (591.5 ml) is close to but not identical to a UK pint (568.3 ml). When a UK recipe calls for a pint, use 568 ml, not 473 ml (US pint) or 591 ml (20 fl oz US bottle).
Worked Examples
Example 1
Convert 12 fl oz of orange juice to milliliters
- Volume
- 12 US fl oz
- Factor
- 29.5735 ml / fl oz
Multiply fluid ounces by the conversion factor.
12 × 29.5735 = 354.882Round to a practical precision.
≈ 354.9 ml
12 fl oz of orange juice = 354.9 ml. This matches the nominal fill of a standard 355 ml (12 fl oz) aluminum can — the 0.1 ml difference is manufacturing tolerance, not a rounding error.
Beverage cans are labeled in both fl oz and ml. A US 12 fl oz can is marketed as 355 ml because 354.88 ml rounds to 355 ml at the nearest whole milliliter. This is consistent across all major US soft-drink and beer producers.
Example 2
Convert a 750 ml wine bottle to US fluid ounces
- Volume
- 750 ml
- Factor
- 29.5735 ml / fl oz
Divide milliliters by the factor to get fluid ounces.
750 ÷ 29.5735 = 25.3606Round to one decimal.
≈ 25.4 fl ozExpress as standard wine pours (5 fl oz each).
25.4 ÷ 5 = 5.08 pours
A 750 ml wine bottle contains 25.4 US fl oz, yielding approximately 5 standard 5 fl oz pours with a small remainder.
The FDA-recommended standard wine serving is 5 fl oz (147.9 ml). A bottle of 750 ml therefore contains 5.07 servings — which is why the Dietary Guidelines cite “5 glasses per bottle” rather than an exact integer.
How to Use This Converter
- Enter the volume in US fluid ounces in the field above.
- The result shows the equivalent in milliliters instantly, using the exact 29.5735 ml/fl oz factor.
- Working with cups instead? Use the cups to ounces converterfirst, then this one — or go straight to cups with the ml to cups converter.
Common Mistakes
- Using the UK fluid ounce factor when you mean the US one.The 4% difference between 29.57 ml (US) and 28.41 ml (UK) is invisible on a single ounce but reaches 19 ml on a pint — enough to change carbonation, recipe balance, or medication concentration meaningfully. When a recipe says “fl oz,” its country of origin determines which factor applies. American recipes: 29.5735 ml. British, Australian, and older Commonwealth recipes: 28.4131 ml.
- Assuming 1 fl oz ≈ 30 ml for precise work.The rounded 30 ml introduces a 0.14% overstatement per ounce. At 16 fl oz that is a 2.3 ml excess — nearly half a teaspoon — which matters in pharmacology, cosmetics formulation, and regulatory labeling where exact milliliter fill weights are required. Use 29.5735 for any quantity above a single drink measure.
- Confusing fluid ounces with weight ounces.“8 oz of cream cheese” on a block is a weight measurement (227 g), not 8 fl oz (236.6 ml). Fluid ounces only apply to volumes of liquid (or pourable) materials. Any time a solid ingredient is measured by “oz” in a recipe, it is weight.
- Treating the 240 ml “cup” as a standard cup.The FDA’s nutrition-label convention uses 240 ml as the reference cup for beverages. The legal US customary cup is 236.588 ml = 8 fl oz. If you see 240 ml = 1 cup on a food label, that is the FDA labeling convention, not the NIST-defined measurement standard.
Background
How the US Fluid Ounce Got Its Milliliter Value
The fluid ounce has parallel histories in the US and UK that diverged from the same medieval English root but ended up at slightly different values. Both systems inherited the concept of an ounce as a small liquid measure from pre-modern English trade. The split came from how each nation defined the gallon that sits at the top of the hierarchy.
The US adopted the Queen Anne wine gallon of 231 cubic inches in 1707, before independence. Because an inch was not yet tied to the metric system, this definition produced a gallon of approximately 3.785 liters. Divided into 128 fluid ounces (8 fl oz to a cup, 2 cups to a pint, 2 pints to a quart, 4 quarts to a gallon), that gallon yields 29.57 ml per fluid ounce [1].
The UK took a different path. Parliament defined the Imperial gallon in 1824 as the volume of 10 pounds of water at 62°F — approximately 4.546 liters. Divided into 160 Imperial fluid ounces (a pint is 20 fl oz in the UK, not 16), the Imperial gallon yields 28.41 ml per fluid ounce. This is why the same recipe using 'a pint' means 473 ml in the US and 568 ml in the UK. The two systems quietly diverged for 150 years before metrication made the discrepancy obvious [2].
The explicit tie between US customary and SI units was formalized in 1959 when the inch was defined as exactly 25.4 mm (making 1 cubic inch = 16.387064 ml exactly). With the gallon fixed at 231 in³ and the inch fixed in millimeters, the US fluid ounce became 29.5735295625 ml exactly — a value that traces back to a colonial-era wine-trade gallon and an 18th-century inch. NIST Handbook 44 preserves this value as the official US legal standard for measuring devices [1].
- NIST Handbook 44, Appendix C — General Tables of Units of Measurement · National Institute of Standards and Technology · 2024
- NIST Special Publication 811 — Guide for the Use of the International System of Units (SI) · National Institute of Standards and Technology · 2008
Fluid Volume Terms
Quick reference
Fluid ounces, milliliters & volume glossary
US Fluid Ounce (fl oz)
1/128 of a US gallon = 29.5735 ml. The standard US small-volume liquid measure.
- The US fluid ounce equals 2 tablespoons = 6 teaspoons = 1/8 US cup. It is defined by the US gallon (231 in³) and the international inch (25.4 mm). Not to be confused with the avoirdupois ounce (weight) or the UK fluid ounce.
UK / Imperial Fluid Ounce
1/160 of an Imperial gallon = 28.4131 ml. About 4% smaller than the US fluid ounce.
- The UK fluid ounce descends from the Imperial gallon (4.54609 liters exactly since 1985). A UK pint is 20 fl oz (568 ml); a US pint is 16 fl oz (473 ml). British, Australian, and older Commonwealth recipes use the Imperial ounce. Modern UK recipes commonly use ml instead, avoiding the ambiguity entirely.
Milliliter (ml)
1/1,000 of a liter. The standard SI small-volume unit, equal to 1 cubic centimeter (cc).
- The milliliter is defined exactly in terms of the meter, which since 1983 is defined by the speed of light. This makes ml a fundamentally stable unit. In medicine, cosmetics, and international food labeling, ml is the preferred volume unit because it is unambiguous — unlike fl oz, which depends on which national gallon you use.
The 30 ml approximation
A common rounding of 1 fl oz ≈ 30 ml. Accurate to 1.4%; fine for cocktails, not for formulations.
- The 30 ml shortcut is taught because it is mentally convenient: 2 fl oz = 60 ml, 4 fl oz = 120 ml, 8 fl oz = 240 ml. Note the 240 ml value that results from 8 × 30 is the FDA nutrition-label cup, not the exact US customary cup (236.588 ml). The discrepancy is 3.4 ml — less than a teaspoon — and safe for casual kitchen use.
US Gallon
231 cubic inches = 3,785.41 ml = 128 US fl oz. The top of the US customary liquid volume hierarchy.
- The US gallon traces to the Queen Anne wine gallon of 1707. The US also has a dry gallon (268.8 in³) used for grain; this is different from the liquid gallon. Most 'gallon' references in the US mean the liquid gallon. The Imperial gallon (UK) is 277.4 in³ ≈ 4,546 ml — about 20% larger.
Shot (jigger)
1.5 US fl oz = 44.4 ml in US bartending. A 'shot' glass can hold 1–2 fl oz depending on style.
- The US standard jigger is 1.5 fl oz (44.36 ml). A 'short shot' is 1 fl oz (29.57 ml). The UK standard single measure is 25 ml (slightly under 1 US fl oz); a UK double is 50 ml. International recipes using 'shots' should specify ml to avoid ambiguity.
Standard Drink (US)
14 g of pure alcohol. For wine (12% ABV) this is 5 fl oz (147.9 ml); for spirits (40% ABV) it is 1.5 fl oz (44.4 ml).
- The CDC and NIAAA define a US standard drink as containing 14 grams of ethanol. Because different beverages have different ABV, the volume per standard drink varies: 12 fl oz of 5% beer, 5 fl oz of 12% wine, or 1.5 fl oz of 40% distilled spirits each deliver approximately 14 g of alcohol.
cc (cubic centimeter)
Exactly equal to 1 ml. Used in medicine, surgery, and automotive contexts rather than cooking.
- cc and ml are interchangeable for all practical purposes: 1 cc = 1 ml = 1 cm³ exactly. Medical syringes are commonly labeled in cc. An 'injection of 10 cc' is 10 ml. The ml notation has largely replaced cc in pharmaceutical and laboratory contexts, but cc persists in surgery and informal medical speech.
Related Converters and Tools
To convert cups to fluid ounces first, see the cups to ounces converter. For the reverse — milliliters to cups — the ml to cups converter gives you direct cooking-friendly results. For grams-to-ounces weight conversions (a different unit entirely), use the all-in-one unit converter.
Frequently Asked Questions
The most common questions we get about this calculator — each answer is kept under 60 words so you can scan.
What is the fluid ounces to milliliters conversion factor?
1 US fl oz = 29.5735 ml. To convert, multiply your fluid ounces value by 29.5735.What is 8 fluid ounces in milliliters?
8 fluid ounces = 236.59 milliliters. Multiply 8 by 29.5735 to get the result.How do I convert milliliters back to fluid ounces?
Divide your milliliters value by 29.5735 (or multiply by the reciprocal). The page shows the exact reverse rate.Is this conversion exact or rounded?
The factor itself is exact by international standard; only the displayed result is rounded for readability. Internally full precision is kept.Is the Oz to Ml converter free?
Yes — free, instant, no signup. All math runs in your browser; nothing is stored.