When cooking, baking, or mixing drinks, you’ll often need to convert between fluid ounces and milliliters. While these two units both measure volume, they use different standards, so converting between them requires a conversion factor. Understanding how many milliliters are in an ounce allows you to seamlessly transition between recipes from different countries.
Quick Answer
There are approximately 29.57 milliliters (mL) in 1 fluid ounce (fl oz). This conversion factor allows you to quickly convert between the two units.
The Definition of a Fluid Ounce
A fluid ounce is a unit of volume used in both the US customary system and the British imperial system. It is equal to 1/128 of a US gallon or 1/160 of an imperial gallon.
There are two types of fluid ounces:
- US fluid ounces – abbreviated as fl oz (US)
- Imperial fluid ounces – abbreviated as fl oz (Imp)
The US fluid ounce is based on the US gallon, which contains 128 fl oz. It is equal to 29.5735295625 mL.
The imperial fluid ounce is based on the imperial gallon, which contains 160 fl oz. It is equal to 28.413 mL.
Key Points on Fluid Ounces
- A fluid ounce is a unit of volume used in the US and British imperial system
- There are two types: US fl oz and imperial fl oz
- 1 US fluid ounce = 29.5735295625 mL
- 1 imperial fluid ounce = 28.413 mL
When a recipe simply lists “fluid ounces” without specifying US or imperial, it is usually safe to assume it means US fluid ounces.
The Definition of Milliliters
The milliliter (mL) is a unit of volume in the metric system. It is equal to 1/1000 of a liter.
1 liter is equal to 1000 mL. This makes the milliliter one of the basic units of volume in the metric system, along with the liter.
The milliliter is commonly used for measuring volumes of liquids in cooking, pharmaceuticals, and scientific experiments. Recipes from countries like Australia, Canada, and the UK will generally list liquid ingredients in milliliters rather than fluid ounces.
Key Points on Milliliters
- The milliliter (mL) is a metric unit of volume
- 1 mL = 1/1000 of a liter
- It is commonly used to measure liquids in recipes, science, and medicine
The milliliter is one of the most widely recognized and used units in the metric system. Its definition directly relates it to the liter, making conversion easy.
Converting Between Fluid Ounces and Milliliters
To convert between fluid ounces and milliliters, you need to use a conversion factor. This is a simple ratio that relates the two units.
For US fluid ounces, the conversion factor is:
- 1 US fl oz = 29.5735295625 mL
For imperial fluid ounces, the conversion factor is:
- 1 imperial fl oz = 28.413 mL
Let’s look at some examples of converting between the two units:
US Fluid Ounces to Milliliters
To convert from US fluid ounces to milliliters, multiply the number of fl oz by 29.5735295625:
- 12 fl oz x 29.5735295625 mL / 1 fl oz = 354.88235075 mL
So 12 US fl oz equals 354.88 mL.
Milliliters to US Fluid Ounces
To convert from milliliters to US fluid ounces, divide the number of mL by 29.5735295625:
- 500 mL / 29.5735295625 mL / 1 fl oz = 16.91 fl oz
So 500 mL equals 16.91 US fl oz.
Imperial Fluid Ounces to Milliliters
To convert from imperial fluid ounces to milliliters, multiply the number of fl oz by 28.413:
- 5 imperial fl oz x 28.413 mL / 1 fl oz = 142.07 mL
So 5 imperial fl oz equals 142.07 mL.
Milliliters to Imperial Fluid Ounces
To convert from milliliters to imperial fluid ounces, divide the number of mL by 28.413:
- 750 mL / 28.413 mL / 1 fl oz = 26.4 fl oz (Imp)
So 750 mL equals 26.4 imperial fl oz.
Conversion Table
This handy table summarizes the conversion factors between US fluid ounces, imperial fluid ounces, and milliliters:
| US Fluid Ounces | Milliliters |
|---|---|
| 1 fl oz | 29.57 mL |
| 2 fl oz | 59.15 mL |
| 3 fl oz | 88.72 mL |
| 4 fl oz | 118.3 mL |
| 5 fl oz | 147.9 mL |
| 6 fl oz | 177.4 mL |
| 7 fl oz | 206.9 mL |
| 8 fl oz | 236.6 mL |
| 9 fl oz | 266.2 mL |
| 10 fl oz | 295.7 mL |
| 11 fl oz | 325.3 mL |
| 12 fl oz | 354.9 mL |
| 13 fl oz | 384.5 mL |
| 14 fl oz | 414.0 mL |
| 15 fl oz | 443.6 mL |
| 16 fl oz | 473.2 mL |
| Imperial Fluid Ounces | Milliliters |
|---|---|
| 1 fl oz | 28.4 mL |
| 2 fl oz | 56.8 mL |
| 3 fl oz | 85.2 mL |
| 4 fl oz | 113.7 mL |
| 5 fl oz | 142.1 mL |
| 6 fl oz | 170.5 mL |
| 7 fl oz | 198.9 mL |
| 8 fl oz | 227.3 mL |
| 9 fl oz | 255.8 mL |
| 10 fl oz | 284.2 mL |
| 11 fl oz | 312.6 mL |
| 12 fl oz | 341.0 mL |
| 13 fl oz | 369.4 mL |
| 14 fl oz | 397.9 mL |
| 15 fl oz | 426.3 mL |
| 16 fl oz | 454.7 mL |
Common Conversions
Here are some of the most common conversions between US fluid ounces and milliliters:
- 1 fl oz = 30 mL (rounded)
- 2 fl oz = 60 mL
- 1/4 cup = 2 fl oz = 59 mL
- 1/3 cup = 3 fl oz = 89 mL
- 1/2 cup = 4 fl oz = 118 mL
- 2/3 cup = 5 fl oz = 148 mL
- 3/4 cup = 6 fl oz = 177 mL
- 1 cup = 8 fl oz = 237 mL
As you can see, common US cooking measurements like cups, thirds, quarters, and halves relate neatly to fluid ounces. Memorizing some of these more useful conversions can help in the kitchen.
Tips for Converting Fluid Ounces and Milliliters
Here are some useful tips for converting fluid ounces and milliliters:
- Double check which type of fluid ounce is being used – US or imperial
- Memorize the basic conversions like 1 fl oz = 30 mL or 1 cup = 237 mL
- When converting milliliters to fluid ounces, round to the nearest 0.25 fl oz to make it easier
- To convert milliliters to cups, divide by 240 mL per cup
- When doubling a recipe, double the volume in milliliters or fluid ounces
- Use a digital kitchen scale to weigh liquids if you don’t have suitable measuring cups
- Check your conversions – make sure the volumes seem sensible
The Difference Between Fluid Ounces and Ounces
It’s important not to confuse fluid ounces, used to measure volume, with ounces, used to measure weight.
While they share the same name, they are completely different units:
- 1 fluid ounce = 29.57 mL
- 1 ounce = 28.35 grams
Ounces measure the weight or mass of something, like 5 oz of chicken. Fluid ounces measure the volume or capacity, like 5 fl oz of milk.
The same name can lead to the misconception that they are interchangeable, but converting between them will give completely inaccurate results. Be sure to pay attention to the terminology when following recipes to avoid mixing them up.
Key Differences
| Fluid Ounce | Ounce | |
|---|---|---|
| Measures | Volume | Weight |
| Abbreviation | fl oz | oz |
| System | US Customary | Avoirdupois |
| Metric Equivalent | 29.57 mL | 28.35 g |
| Used for | Liquids | Solids |
Converting Between Cups, Tablespoons and Teaspoons
In cooking, you’ll also need to convert between cups, tablespoons (tbsp), and teaspoons (tsp). Here are some handy conversions:
- 1 cup = 16 tbsp
- 1 cup = 48 tsp
- 1 tbsp = 3 tsp
- 1/2 cup = 8 tbsp
- 1/4 cup = 4 tbsp
- 2 tbsp = 6 tsp
- 1 1/2 tsp = 1/2 tbsp
These don’t involve fluid ounces directly, but are useful alongside fl oz conversions when following recipes.
Converting Fluid Ounces to Grams and Liters
In some cases you may need to convert fluid ounces to grams (g) and liters (L). Here are the main conversion factors:
- 1 fl oz = 28.4 g
- 1 fl oz = 0.03 L
- 1 L = 33.8 fl oz
- 1 kg = 35.2 fl oz
So for example:
- 4 fl oz = 113 g
- 16 fl oz (1 US pint) = 0.47 L
- 2 L = 67.6 fl oz
Conclusion
Converting between fluid ounces and milliliters is straightforward using the right conversion factors. Memorizing some of the more common conversions can help, but if in doubt, use the exact figures:
- 1 US fl oz = 29.57 mL
- 1 imperial fl oz = 28.41 mL
Be careful not to mix up fluid ounces, which measure volume, with ounces, which measure weight. Finally, don’t forget about converting between cups, tablespoons and teaspoons. Mastering these crucial cooking conversions will allow you to easily double recipes, convert between metric and imperial measurements, and have confidence working with any cookbook or recipe from around the world.