US Fluid Ounces To Millilitres Converter

US Fluid Ounce Formula

The US customary fluid ounce is about 29.57 mL. It appears in many American recipes, nutrition labels, water bottle sizes, drink servings and measuring cups. A UK imperial fluid ounce is about 28.41 mL, so the difference is small per ounce but grows across a batch.

How To Choose The Right Ounce

US fl oz To mL Table

Worked Conversion Examples

Recipe And Label Notes

For home cooking, rounding to the nearest millilitre is usually enough. If you are scaling a recipe, convert all liquid ingredients using the same system before multiplying the batch. For nutrition labels, use the serving volume printed by the manufacturer because serving size can be rounded for labelling. For cocktails or brewing, record whether the original source used US or UK fluid ounces so the method can be repeated.

Do not use this converter for dry ounces. Dry ounces are weight, not volume. Flour, sugar, butter, rice and oats need ingredient-specific weight conversions because density changes from one ingredient to another.

US drink labels often use serving sizes such as 8, 12 or 16.9 US fluid ounces. Those numbers can look odd in the UK because the metric equivalent is the more familiar label: about 237 mL, 355 mL and 500 mL. The converter helps you move between the packaging language and a metric jug or bottle size.

When A US fl oz Converter Is The Right Choice

Use this page when the source is clearly American: a US nutrition facts panel, a US cookbook, an imported bottle, an American cocktail recipe or a measuring cup marked in US cups. A US cup is 8 US fluid ounces, not an imperial cup. If the recipe uses Australian metric cups, UK imperial pints or spoon measures, check those separately before scaling the recipe.

For batches, convert once and then scale. For example, if a recipe uses 12 US fl oz of stock and you need three batches, convert 12 US fl oz to about 355 mL, then multiply by three. That avoids rounding each serving separately and creating a small cumulative error.

For imported drinks, the US fluid ounce label may sit beside a metric volume that has already been rounded for packaging. If the label says 16.9 fl oz and 500 mL, both are intended to describe the same bottle. Use the metric figure for UK stock sheets, price labels or nutrition comparisons, and keep the US figure only where the original packaging language is useful.

For recipes that mix fluid ounces and tablespoons, convert both units from the same US system before adding. A US tablespoon is commonly treated as half a US fluid ounce, about 14.79 mL. Mixing a UK tablespoon with a US fluid ounce can create a small but avoidable error.

For nutrition tracking, use the serving size on the label rather than a rounded household cup if the two differ. A small rounding difference per serving can become noticeable when a bottle contains several servings or when a recipe is logged repeatedly across a week.

For stock control, keep both the bottle size and the converted millilitres in your spreadsheet so purchasing, shelf labels and recipe costing all use the same volume basis.

Sources

• National Institute of Standards and Technology. (2008). Guide for the Use of the International System of Units. NIST. https://www.nist.gov/pml/special-publication-811
• International Bureau of Weights and Measures. (2019). The International System of Units (SI), 9th ed. BIPM. https://www.bipm.org/en/publications/si-brochure
• U.S. Food and Drug Administration. (n.d.). Food labeling and nutrition. FDA. https://www.fda.gov/food/food-labeling-nutrition