A fast, bidirectional oz to ml converter
Whether you are following a recipe from an American cookbook, mixing a cocktail, measuring out liquid medication, or checking airline travel limits, you will frequently need to convert oz to ml. This calculator provides an instant, bidirectional way to translate US fluid ounces into milliliters.
Because the tool runs entirely locally in your web browser, there are no server delays or page reloads. You can type your value into either box—change the ounces to see the milliliters update, or type in the milliliters to instantly get the equivalent in fluid ounces. None of your input is ever uploaded or saved, ensuring a fast and private experience.
How to convert fluid ounces to ml
The math behind the conversion is straightforward but difficult to do in your head because of the decimals involved. The exact formula is:
1 US fl oz = 29.5735296 ml
To convert fluid ounces to milliliters manually, you multiply your ounce value by 29.5735296. For example, if a recipe calls for 8 fluid ounces of milk, you multiply 8 by 29.5735296 to get approximately 236.59 milliliters.
If you need to go the other way and convert ml to oz, you divide your milliliter amount by 29.5735296. For instance, a 750 ml bottle of wine divided by 29.5735296 equals just over 25.3 fluid ounces.
For everyday kitchen use, most people round one fluid ounce to 30 ml. However, when scaling up recipes for commercial use, brewing coffee, or mixing precise chemical solutions, using the exact decimal is critical to avoid compounding errors. This calculator preserves up to 8 significant digits to ensure your measurements remain perfectly accurate.
US vs. Imperial fluid ounces
One of the most common points of confusion in volume measurement is the difference between the US customary system and the British Imperial system. While both systems use the term "fluid ounce," the actual volume they represent is slightly different.
- US Fluid Ounce: 29.5735296 ml
- Imperial Fluid Ounce: 28.4130625 ml
This tool is specifically designed to convert US fluid ounces to milliliters, as the US system is the most widely encountered on global nutrition labels, American recipes, and imported consumer goods. If you are using a vintage British or Australian recipe book, be aware that their fluid ounces are slightly smaller.
Common volume conversions in everyday life
Understanding how to convert fl oz to milliliters is incredibly useful in a variety of everyday situations. Here are a few common scenarios where these measurements apply:
Travel and TSA limits: If you travel through airport security in the United States, you are subject to the 3-1-1 liquids rule. The TSA limits liquid containers to 3.4 fluid ounces. If you buy travel bottles in Europe or Asia, you will see them labeled as 100 ml. Our converter shows that 3.4 oz is exactly 100.55 ml, which is why 100 ml is the international standard for carry-on liquids.
Baby bottles and formula: Infant formula is often measured in both ounces and milliliters. A standard baby bottle might hold 4 oz or 8 oz of liquid. Using the converter, you can see that a 4 oz feed is roughly 120 ml, and an 8 oz feed is about 240 ml.
Coffee brewing: Specialty coffee recipes often require precise ratios of water to coffee grounds. A standard American coffee mug holds about 12 fl oz, which translates to roughly 355 ml of water.
Bartending and mixology: A standard shot glass in the US holds 1.5 fluid ounces. If you are using a metric jigger to mix drinks, you will need to measure out approximately 44 ml of liquor per shot.
Fluid ounces vs. dry ounces
It is important to remember that this tool is for measuring volume, not weight. A fluid ounce (fl oz) measures how much physical space a liquid occupies. A standard ounce (oz) measures how heavy something is.
For water, the two measurements are nearly identical: 1 fluid ounce of water weighs approximately 1 ounce. However, for liquids with different densities, this rule falls apart. One fluid ounce of honey is much heavier than one ounce, while one fluid ounce of whipped cream is much lighter. Always ensure you are converting liquid volume (fl oz to ml) rather than trying to convert a dry weight into a liquid measure.
If you need to convert other common kitchen measurements, you can use our related tools to convert ml to cups, switch between tablespoons and teaspoons, or scale up larger volumes by converting liters to gallons.