Fluid Ounce to mL Converter

A fluid ounce to milliliter conversion translates a volume measurement from the imperial or US customary system to the metric system. This converter uniquely supports both US and UK fluid ounces, which are different units despite sharing the same name. The US fluid ounce equals exactly 29.5735 mL, while the UK (Imperial) fluid ounce equals exactly 28.4131 mL. This distinction is critical because using the wrong fluid ounce standard can introduce a volume error of about 4%, which is significant in cooking, pharmaceutical compounding, and laboratory work.

The fluid ounce is a unit of volume, not weight. One US fluid ounce of pure water at 4°C weighs approximately 1.04 avoirdupois ounces, but this relationship changes for other liquids depending on their density. The fluid ounce gets its name from the fact that it was originally defined by the weight of water, but modern definitions are based on volume. The US fluid ounce is one-twelfth of a US liquid gallon, while the Imperial fluid ounce is one-twentieth of an Imperial gallon.

This converter provides conversions to milliliters, liters, cups, and tablespoons, giving you a comprehensive view of the volume in multiple useful units. The additional conversions are especially helpful in the kitchen, where a recipe might call for ingredients in any of these units depending on the source. The converter also clearly shows the conversion factor for each fluid ounce type so you can verify the accuracy of the calculation.

The formula depends on which type of fluid ounce you are converting. Both conversions multiply the input value by a conversion factor specific to the fluid ounce standard.

Use this calculator to convert US or UK fluid ounces to milliliters and other units:

1. Enter the fluid ounces: Type the number of fluid ounces into the input field. You can use whole numbers, decimals, or fractions expressed as decimals.
2. Select the fluid ounce type: Choose between US Fluid Ounce (29.5735 mL per fl oz) and UK Fluid Ounce (28.4131 mL per fl oz) from the dropdown menu.
3. Read the primary result: The main result card shows the conversion to milliliters, computed using the selected type's conversion factor.
4. View all conversions: Below the primary result, you can see the equivalent values in liters, cups, and tablespoons.
5. Check the fluid ounce type reference: The reference section shows the milliliter value for each fluid ounce type so you can compare them directly.

The quick reference section provides common conversions for both US and UK fluid ounces.

The calculator provides four equivalent volume measurements:

• Milliliters (mL): The primary metric result. Found by multiplying fluid ounces by the conversion factor for the selected type. This is the standard unit for precise liquid measurements in cooking, medicine, and science.
• Liters (L): The larger metric unit, found by dividing milliliters by 1,000. Useful for understanding total container volumes and for scaling recipes to larger quantities.
• Cups: Found by dividing milliliters by 236.588 (for US cups). Useful for following American recipes that use cup measurements.
• Tablespoons: Found by dividing milliliters by 14.787. Useful for measuring small quantities of liquid ingredients in the kitchen.

The fluid ounce type reference shows that US and UK fluid ounces differ by about 4%. A UK fluid ounce is slightly smaller than a US fluid ounce. This difference is small enough to go unnoticed in casual cooking but can be significant in precise applications like pharmaceutical compounding or laboratory measurements.

This conversion is essential in international cooking and baking. American recipes typically specify liquid ingredients in US fluid ounces, cups, or tablespoons, while British, Australian, and European recipes may use UK fluid ounces or milliliters. When following a recipe from a different country, knowing which fluid ounce standard is being used prevents measurement errors. For example, a British recipe calling for 8 UK fl oz of milk requires 227.3 mL, while an American recipe calling for 8 US fl oz requires 236.6 mL.

In pharmaceutical compounding, precise volume measurements are critical for patient safety. Medication dosages must be measured accurately, and different countries may use different fluid ounce standards in their药学 references. Pharmacists must be able to convert between fluid ounces and milliliters with high precision to ensure that patients receive the correct dosage of liquid medications.

In beverage industries, product sizes vary significantly between the US and UK markets. A US beer is typically 12 fl oz (355 mL), while a UK beer pint is 20 Imperial fl oz (568 mL). Soft drinks, juices, and dairy products all have different standard sizes depending on the market. Understanding the fluid ounce type distinction helps consumers, manufacturers, and retailers compare products accurately across international boundaries.