Fluid ounces to milliliters (fl oz to ml) converter

What is a fluid ounces to milliliters converter?

A fluid ounces to milliliters converter is an online tool that turns a volume expressed in fluid ounces into its equivalent in milliliters, and back again. The fluid ounce belongs to the customary systems used in the United States and the United Kingdom, while the milliliter is the everyday small-volume unit of the metric system. Because labels, recipes, and product specifications often switch between these systems depending on the country, having a quick way to translate between fl oz and mL removes guesswork and keeps your measurements consistent.

American and English fluid ounces

There are two fluid ounces in common use, and they are not the same size. The US fluid ounce (US fl oz) is equal to about 29.5735 milliliters, while the UK (Imperial) fluid ounce (UK fl oz) is slightly smaller at about 28.4131 milliliters. The difference is small but real, so it matters when you are scaling a recipe or matching a spec sheet. US measurements dominate in North America, whereas the UK fluid ounce appears on British and some Commonwealth packaging.

How does the converter work?

The converter holds a fixed conversion factor for each fluid-ounce type and applies it to whatever number you enter. Type a value into the fluid ounces field and the milliliters field updates instantly; type a value into the milliliters field and the fluid ounces field is recalculated in reverse. You can switch the fluid-ounce unit between US and UK and choose whether the metric side is shown in milliliters or liters, and the result follows your selection.

Formula for conversion

To convert between fluid ounces and milliliters, use the factor that matches your fluid-ounce type:

For US fluid ounces to milliliters: $\text{mL} = \text{US fl oz} \times 29.5735$

For milliliters to US fluid ounces: $\text{US fl oz} = \text{mL} \times 0.033814$

For UK fluid ounces to milliliters: $\text{mL} = \text{UK fl oz} \times 28.4131$

For milliliters to UK fluid ounces: $\text{UK fl oz} = \text{mL} \times 0.035195$

Conversion table

The table below lists common fluid-ounce amounts and their milliliter equivalents for both the US and UK fluid ounce:

Examples

Example 1: One US fluid ounce

Convert 1 US fluid ounce to milliliters using the factor 29.5735:

$1 \text{ US fl oz} \times 29.5735 = 29.5735 \text{ mL}$

Example 2: A standard cup of liquid

A US cup is 8 fluid ounces. Converting 8 US fluid ounces to milliliters gives:

$8 \text{ US fl oz} \times 29.5735 = 236.588 \text{ mL}$

Example 3: One UK fluid ounce

The Imperial fluid ounce is smaller. Converting 1 UK fluid ounce to milliliters gives:

$1 \text{ UK fl oz} \times 28.4131 = 28.4131 \text{ mL}$

Example 4: Milliliters back to fluid ounces

Going the other way, 29.5735 milliliters converts back to exactly 1 US fluid ounce:

$29.5735 \text{ mL} \times 0.033814 = 1 \text{ US fl oz}$

Notes

• Always check whether a value is a US or UK fluid ounce before converting, since the two differ by roughly 1.1 mL each.
• The fluid ounce is a unit of volume, not weight; 1 fl oz of water weighs close to its volume in grams, but oils, syrups, and other liquids do not.
• For larger amounts you can switch the metric output to liters; 1000 mL equals 1 liter.
• Using one consistent unit throughout a recipe or specification helps avoid rounding errors.

Frequently asked questions

How many milliliters are in 1 fluid ounce?

One US fluid ounce is equal to about 29.5735 milliliters, while one UK (Imperial) fluid ounce is about 28.4131 milliliters.

What is the difference between a US and a UK fluid ounce?

The US fluid ounce is slightly larger, at roughly 29.5735 mL, compared with the UK fluid ounce at roughly 28.4131 mL. The gap is about 1.16 mL per ounce, which adds up over several ounces.

How many milliliters are in 8 fluid ounces?

Eight US fluid ounces equal 236.588 milliliters. This is the volume of a standard US cup.

How do I convert milliliters back to fluid ounces?

Multiply the number of milliliters by 0.033814 for US fluid ounces, or by 0.035195 for UK fluid ounces. For example, 29.5735 mL equals 1 US fluid ounce. If you prefer the reverse direction by default, you can use our milliliters to fluid ounces converter.

Is the fluid ounce a measure of volume or weight?

The fluid ounce measures volume. It should not be confused with the avoirdupois ounce, which measures weight (mass).

Why might my conversion look slightly off?

Make sure you have selected the correct fluid-ounce type (US versus UK). Small differences usually come from mixing the two systems or from rounding the conversion factor.