How to convert fluid ounces to milliliters
To convert fluid ounces to milliliters, multiply the fluid-ounce value by the conversion factor for the measurement system being used.
Milliliters (US Customary) = US fl oz × 29.57353
Milliliters (Imperial) = UK fl oz × 28.41306
Example: 8 US fl oz (1 Standard US Cup)
8 × 29.5735 = 236.59 ml
Quick mental math shortcut
For rough kitchen measurements, you can use 1 US fl oz ≈ 30 ml. This is convenient for mental calculations, but it is a rounded approximation. For example, 8 US fl oz is approximately 240 ml, while the exact conversion is 236.59 ml.
US Customary vs. Imperial fluid ounces
A common cause of recipe failures is confusing US and Imperial fluid ounces:
- US Customary fluid ounce: 1 US fl oz = 29.5735295625 mL.
- Imperial fluid ounce: 1 Imperial fl oz = 28.4130625 mL.
An Imperial fluid ounce is about 4% smaller than a US fluid ounce, so the distinction matters when converting recipes, beverage volumes, and other measurements.
For broader volume conversions, see our US Volume Converter and UK Volume Converter.
Common fluid ounce and beverage volumes
These examples show how common fluid-ounce quantities convert to milliliters under the US Customary and Imperial systems.
| Fluid Ounces (fl oz) | US Equivalent (ml) | Imperial Equivalent (ml) | Common Context |
|---|---|---|---|
| 1.5 fl oz | 44.36 mL | 42.62 mL | Common jigger/shot size |
| 8 fl oz | 236.59 mL | 227.30 mL | US customary cup |
| 12 fl oz | 354.88 mL | 340.96 mL | Common beverage size |
| 16.9 fl oz | 500.26 mL | 480.19 mL | Common 500 mL bottle size |
| 20 fl oz | 591.47 mL | 568.26 mL | Imperial pint |
| 24 fl oz | 709.76 mL | 681.91 mL | Common large beverage size |
| 32 fl oz | 946.35 mL | 909.22 mL | US liquid quart |
| 128 fl oz | 3,785.41 mL | 3,636.87 mL | US gallon |
Common fluid ounce conversions
These common US fluid ounce conversions are useful for recipes, beverages, and everyday volume measurements.
Frequently asked questions
How many ml is 1 fluid ounce?
One US fluid ounce equals 29.57 mL, while one Imperial fluid ounce equals 28.41 mL. For rough kitchen measurements, 1 US fl oz is often rounded to 30 mL.
How many ml is in a 16.9 oz water bottle?
A 16.9 US fl oz water bottle is approximately 500 ml. More precisely, 16.9 US fl oz is about 499.79 ml.
Is fluid ounces (fl oz) the same as weight ounces (oz)?
No. Fluid ounces measure volume, while ounces normally measure mass. They cannot be directly substituted unless the density of the substance is known. For water, 1 US fl oz has a mass of roughly 1.04 oz under typical conditions.
How many ml is 8 oz of milk or water?
8 US fluid ounces of milk or water equals 236.59 mL. The liquid type does not change the volume conversion because fluid ounces measure volume.