A US fluid ounce is 1/128 of a US gallon.
Fluid ounces to Milliliters Converter — fl oz to mL
Convert Fluid ounce (fl oz) to Milliliter (mL) using the exact conversion factor (1 fluid ounce = 29.57352956 milliliter). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Fluid ounces to Milliliters converter
Converter
Volume Converter
Convert metric, US customary, imperial, cooking, dry, and industrial volume units.
Context values
Some unit families need one extra value for a physically accurate result.
Milliliter is 0.001 liter units.
Result = input x 2.95735296e-5 / 1e-6.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Fluid ounces to Milliliters
Fluid ounce and Milliliter appear side by side at fuel pumps and on beverage labels, since the US measures liquids in gallons while most of the world uses liters. Fluid ounce is typically associated with united States (beverage, nutrition labeling), while Milliliter is typically associated with standard small-volume unit worldwide.
Formula
milliliters = fluid ounces × 29.5735295625
This factor comes from each unit's defined relationship to the category's base unit: 1 fluid ounce equals 0.0000295735295625 base units, and 1 milliliter equals 0.000001 base units, so dividing one by the other gives the direct fluid ounce-to-milliliter factor of 29.5735295625.
Simple example
1 fl oz × 29.57352956 = 29.57352956 mL
1 fluid ounce = 29.57352956 milliliters.
Real-world example
10 fl oz × 29.57352956 = 295.7352956 mL
10 fluid ounces = 295.7352956 milliliters.
Conversion table
| Fluid ounce (fl oz) | Milliliter (mL) |
|---|---|
| 1 fl oz | 29.57352956 mL |
| 5 fl oz | 147.8676478 mL |
| 10 fl oz | 295.7352956 mL |
| 25 fl oz | 739.3382391 mL |
| 50 fl oz | 1,478.676478 mL |
| 100 fl oz | 2,957.352956 mL |
Reverse conversion: Milliliter to Fluid ounce
29.57352956 mL × 0.0338140227 = 0.9999999999 fl oz
29.57352956 milliliters = 0.9999999999 fluid ounces.
fluid ounces = milliliters × 0.0338140227018
For a page dedicated to this direction, see Milliliter to Fluid ounce.
Fluid ounce vs. Milliliter
| Aspect | Fluid ounce | Milliliter |
|---|---|---|
| Family | US customary unit | SI derived (metric prefix) unit |
| Typical use | US beverage container sizing (soda, water bottles) | Medicine dosing (worldwide, including in the US) |
| Where it's used | United States (beverage, nutrition labeling) | Standard small-volume unit worldwide |
Understanding the Fluid ounce
Fluid ounce (fl oz) measures volume. The US fluid ounce is 1/128 of a US gallon: exactly 29.5735295625 milliliters. It is classified as a US customary unit.
Where it's used: United States (beverage, nutrition labeling)
Uses of the Fluid ounce today
- US beverage container sizing (soda, water bottles)
- US nutrition and medication dosing labels
History of the Fluid ounce
The US fluid ounce follows from the same English wine-gallon system as the rest of the US liquid volume units, defined as a consistent fraction of the gallon.
Historical origin. Fluid ounce was not the invention of a single named person; it developed through the process described above.
Understanding the Milliliter
Milliliter (mL) measures volume. A milliliter is one-thousandth of a liter, equal to one cubic centimeter. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard small-volume unit worldwide
Uses of the Milliliter today
- Medicine dosing (worldwide, including in the US)
- Cooking and recipe measurement outside the US
- Beverage and small-container labeling
History of the Milliliter
The milliliter follows directly from the liter via the 'milli-' SI prefix. It is notable as one of the few metric units in routine US use, since medicine dosing (syringes, liquid medication) is specified in milliliters even in the US.
Historical origin. Milliliter was not the invention of a single named person; it developed through the process described above.
Fluid ounce — sources
- NIST Handbook 44, Appendix C — General tables of units including the US fluid ounce definition.
Milliliter — sources
- BIPM SI Brochure — SI prefixes — Defines 'milli-' as the prefix for 10⁻³.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many milliliters are in 1 fluid ounce?
1 fluid ounce equals 29.57352956 milliliters, using the exact defined conversion factor rather than an estimate.
How do I convert fluid ounce to milliliter?
Multiply the fluid ounce value by 29.57352956. The converter above does this instantly to whatever precision you set.
How do I convert milliliter back to fluid ounce?
Use the reverse factor: 1 milliliter equals 0.0338140227 fluid ounces. You can also use the swap control in the converter above to flip the direction instantly.
What is a fluid ounce?
Fluid ounce (fl oz) measures volume. The US fluid ounce is 1/128 of a US gallon: exactly 29.5735295625 milliliters. It is classified as a US customary unit.
What is a milliliter?
Milliliter (mL) measures volume. A milliliter is one-thousandth of a liter, equal to one cubic centimeter. It is classified as a SI derived (metric prefix) unit.
Is the fluid ounce to milliliter conversion exact?
Yes. The US fluid ounce is 1/128 of a US gallon: exactly 29.5735295625 milliliters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the fluid ounce still used today?
United States (beverage, nutrition labeling)