🧪 Ml to Oz Converter
Convert millilitres to US fluid ounces and back. The exact factor, a table of the values people look up most, and what each unit is actually used for.
Converting millilitres to US fluid ounces
One millilitre is 0.0338140227 US fluid ounces, and one US fluid ounce is 29.57352956 millilitres.
US fluid ounces = millilitres × 0.0338140227
Getting the precision right
A US fluid ounce is 29.5735 ml; an imperial fluid ounce is 28.4131 ml, about 4% smaller. The gap is small enough to be invisible in a single measurement and large enough to matter across a recipe. Remember too that a fluid ounce measures volume while an ounce measures weight, and they are not interchangeable for anything but water.
Where each unit is used
Millilitres are standard for cooking, medicine and cosmetics almost everywhere. US fluid ounces appear in American recipes and on drink containers, and airline liquid limits are set in both, which is why travel-size bottles are labelled 100 ml and 3.4 fl oz.
Values worth knowing
| ml | fl oz |
|---|---|
| 5 | 0.16907 |
| 15 | 0.50721 |
| 30 | 1.01442 |
| 50 | 1.6907 |
| 100 | 3.3814 |
| 150 | 5.0721 |
| 237 | 8.01392 |
| 250 | 8.45351 |
| 500 | 16.907 |
| 1000 | 33.814 |
A teaspoon is 5 ml. A tablespoon is 15 ml. A US cup is 237 ml or 8 fl oz. The airline carry-on limit of 100 ml is 3.4 fl oz.
Where the two units came from
The fluid ounce was defined as the volume occupied by one ounce of a substance, which meant it depended on what you were measuring. Britain resolved this in 1824 by defining it as the volume of one avoirdupois ounce of water, while the United States defined it as one 128th of its older wine gallon. The two ended up about 4% apart, and because the American one is larger, a US pint is 16 fl oz while an imperial pint is 20.
Round the result to the precision your own work needs. These converters carry the full factor, which is useful for checking but rarely what you want to write down.
Once you have this figure, the liters to gallons is where it usually goes next. the cups to ml is the related one people reach for afterwards.
Frequently Asked Questions (FAQs)
How many millilitres are in a fluid ounce?
29.5735 ml for a US fluid ounce and 28.4131 for an imperial one. The difference is about 4%, which compounds across a recipe with several liquid ingredients.
Is a fluid ounce a measure of weight?
No. It measures volume. The ounce used for weight is a different unit entirely, and they match only for water, and even then only roughly. A fluid ounce of honey weighs about 1.5 ounces.
Why is the airline limit 100 ml and not 3 fl oz?
Because the rule was written in metric and 3.4 fl oz is the conversion, not the other way round. American signage rounds it to 3.4 oz, which is why the two numbers appear together on travel bottles.