Need to convert oz to ml? Whether you're following a recipe from the US, measuring ingredients for baking, mixing cocktails, or dosing medication, converting ounces to milliliters is one of the most common volume conversions people need. This comprehensive guide provides the exact formula, a detailed conversion table from 0.25 oz to 50 oz, a free calculator, and practical examples for everyday use.
The fluid ounce (fl oz) is a unit of volume used primarily in the United States customary system, while the milliliter (ml) is a metric unit of volume used worldwide. The relationship between them is fixed: 1 US fluid ounce equals approximately 29.5735 milliliters. This conversion is essential for anyone who encounters recipes, product labels, or instructions that use a different measurement system than what they're familiar with.
It's important to note the difference between US fluid ounces and UK (imperial) fluid ounces. A US fluid ounce is about 29.57 ml, while a UK fluid ounce is about 28.41 ml — roughly a 4% difference. This guide focuses on US fluid ounces, which are the standard in most online recipes and American product labels. If you're working with UK or Commonwealth recipes, be sure to adjust accordingly.
Volume conversions like oz to ml come up constantly in cooking and baking. Many popular recipes on the internet originate from the US and use fluid ounces, while most of the world measures liquids in milliliters. Having a reliable conversion reference saves time and prevents costly mistakes — especially in baking, where precision matters.
US Fluid Ounces to Milliliters:
ml = oz × 29.5735
UK (Imperial) Fluid Ounces to Milliliters: ml = oz × 28.4131
ml = oz × 28.4131
Quick approximation: ml = oz × 30 (within 1.5% for most values)
ml = oz × 30
The US fluid ounce is defined as exactly 1/128 of a US gallon, which equals approximately 29.5735295625 milliliters. For practical purposes, rounding to 29.57 or even 30 ml per ounce is sufficient for cooking and general use. The milliliter, on the other hand, is defined as exactly 1 cubic centimeter (cm³), making it part of the SI-derived metric system used by virtually every country outside the United States.
When precision matters — such as in pharmaceutical dosing, scientific experiments, or professional baking — use the full conversion factor. For casual cooking, the approximation of 30 ml per ounce works well enough and is easier to calculate mentally.
Enter a volume in fluid ounces
The following table covers the most commonly used fluid ounce measurements, from small cooking measurements to larger volumes. This is the table you'll want to bookmark for quick reference while cooking or mixing drinks.
Many recipes call for fractional measurements. Here are the most common fractions of an ounce converted to milliliters for quick reference.
Example 1: Converting a recipe ingredient
A US recipe calls for 6 fl oz of milk. How many milliliters is that?
ml = 6 × 29.5735 = 177.44 ml
Since most measuring cups have markings for 175 ml or 180 ml, you can round to the nearest marking. In this case, 180 ml is close enough for cooking purposes.
Example 2: Converting a cocktail recipe
A cocktail recipe specifies 2.5 oz of orange juice. Convert to milliliters.
ml = 2.5 × 29.5735 = 73.93 ml
Round to approximately 74 ml or 75 ml for easy measuring with a jigger or graduated cylinder.
Example 3: Converting medication dosage
A children's medicine bottle specifies 1.5 fl oz per dose. How much is that in ml?
ml = 1.5 × 29.5735 = 44.36 ml
Most medicine cups are marked in ml, so you would measure approximately 44 ml (or 45 ml if rounding up for safety). Always follow your doctor's or pharmacist's instructions precisely.
Example 4: Converting a large volume
You need 24 fl oz of water for a sports bottle. Convert to milliliters.
ml = 24 × 29.5735 = 709.77 ml
Round to approximately 710 ml. Many water bottles in metric countries are sized at 700 ml or 750 ml, so this is a convenient conversion to know.
The most frequent use of oz to ml conversion is in the kitchen. American recipes use fluid ounces for liquid ingredients, while most of the world uses milliliters. Common conversions include vanilla extract (1 tsp ≈ 0.17 oz ≈ 5 ml), cooking oil, broth, and water. Baking is especially precision-sensitive — using the wrong amount of liquid can ruin a cake or bread recipe entirely. Having a reliable oz to ml reference is essential for any home baker working from international recipes.
Bar and cocktail recipes almost universally use fluid ounces in the US. A standard shot is 1.5 oz (44 ml), a cocktail typically uses 2-3 oz of spirit (59-89 ml), and mixers are measured similarly. If you're using a jigger or shaker with ml markings but following an American recipe, you'll need to convert frequently. Professional bartenders often memorize the key conversions: 1 oz ≈ 30 ml, 1.5 oz ≈ 45 ml, 2 oz ≈ 60 ml.
Medication dosages, especially for liquid medicines, cough syrups, and children's medications, are sometimes specified in fluid ounces in the US but milliliters everywhere else. Converting accurately is crucial for safety. Most pharmacy-provided dosing cups have both oz and ml markings, but understanding the conversion helps when you only have one type of measuring device available.
The commonly cited recommendation to drink "8 glasses of water a day" often means 8 fl oz glasses, which equals about 237 ml per glass or roughly 1.9 liters total. Understanding oz to ml conversion helps you track your daily water intake accurately, especially when mixing information from US and metric sources. Similarly, nutrition labels on beverages show serving sizes in both systems.
When traveling internationally, you'll encounter products measured in milliliters. A standard US travel-size bottle of 3.4 oz (100 ml) matches the TSA liquid limit for carry-on luggage. Knowing this conversion helps you pack correctly and shop for the right-sized containers when abroad.
One common source of confusion is the difference between US fluid ounces and UK (imperial) fluid ounces. The US fluid ounce is based on the US gallon (128 fl oz per gallon), while the imperial fluid ounce is based on the imperial gallon (160 fl oz per gallon). This means:
If you're following a recipe from a British or Australian cookbook published before metrication (1970s), it likely uses imperial fluid ounces. Modern UK and Australian recipes use milliliters. Always check which system your recipe uses before converting.
Not exactly, but it's a common and useful approximation. 1 US fluid ounce equals 29.5735 ml. Rounding to 30 ml is only about 1.5% off, which is acceptable for cooking and casual measuring. However, for precise applications like medication or laboratory work, use the exact conversion factor.
8 US fluid ounces equal approximately 236.59 ml. This is equivalent to 1 US cup. Many measuring cups are dual-marked with both 8 oz and 237 ml (or 240 ml in some countries) on opposite sides.
16 US fluid ounces equal approximately 473.18 ml. This is equivalent to 1 US pint or 2 cups. A standard US water bottle is typically 16.9 oz (500 ml).
A fluid ounce (fl oz) measures volume (liquids), while a dry ounce (oz) measures weight (mass). They are different units and cannot be converted directly. For example, 1 fluid ounce of water weighs approximately 1.04 dry ounces, but 1 fluid ounce of flour weighs only about 0.53 dry ounces because flour is less dense than water. This guide covers fluid ounces to milliliters (volume to volume) only.
One fluid ounce is approximately 29.57 ml, which is roughly equivalent to 6 teaspoons or 2 tablespoons. If you have standard cutlery, 2 tablespoons is a reasonable approximation of 1 oz. For better accuracy, use a graduated medicine cup or a small measuring spoon set.
In cooking, context matters. If a recipe says "1 oz of flour" or "1 oz of chocolate chips," it usually refers to weight (mass), not volume. But if it says "1 oz of milk" or "1 fl oz of water," it refers to volume. The abbreviation "fl oz" explicitly means fluid ounces (volume). When in doubt, check if other ingredients in the recipe use volume or weight measurements — they'll typically be consistent.
One US gallon equals 3,785.41 ml (or 128 fl oz). One UK (imperial) gallon equals 4,546.09 ml. The difference is significant — nearly 20% — so always confirm which gallon system you're using. See our gallons to liters guide for more details.
Need to make other conversions? Try these free tools from RiseTop:
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Last updated: April 2026. Conversion values are based on the US customary fluid ounce. For precise scientific or medical conversions, always verify with authoritative sources. Use our oz to ml converter for instant calculations.