Convert Milliliter to Fluid Ounce (US)
Conversion Formula
fl oz = mL × 0.033814To convert Milliliter to Fluid Ounce (US), use the formula above. This is the standard conversion factor used worldwide.
Conversion Table
| Milliliter (mL) | Fluid Ounce (US) (fl oz) |
|---|---|
| 1 | 0.033814 |
| 100 | 3.381400 |
| 500 | 16.907000 |
| 1000 | 33.814000 |
Why convert Milliliter to Fluid Ounce (US)
Skincare and cosmetics bottles, especially from Korean, European, or Japanese brands, list volume in milliliters, and comparing that to the fluid ounce sizes US products and TSA carry-on rules use requires converting. Medicine dosing is the other common case: a US liquid medication's dosing cup is often marked in both units, and misreading a milliliter syringe against a fluid ounce instruction is a real source of confusion.
Where the number comes from
This page converts to the US fluid ounce, exactly 29.5735295625 milliliters. That's different from the imperial fluid ounce still used in the UK, 28.4130625 milliliters, a smaller volume despite the larger-sounding 'imperial' name, and the two are close enough that a mismatch is easy to miss but large enough to matter for dosing.
Quick reference
| 1 mL | 0.0338 US fl oz | |
| 1 US fl oz | 29.5735 mL | exact ratio 29.5735295625 |
| 1 imperial fl oz | 28.4131 mL | UK fluid ounce, smaller than the US one |
| 100 mL | 3.3814 US fl oz | the TSA carry-on liquid limit |
| 355 mL | 12 US fl oz | a standard US soda can |
| 500 mL | 16.907 US fl oz | a common water bottle size |
Common mistakes
- Confusing the US and imperial fluid ounce is the core risk here, and it runs backward from what people expect: the imperial fluid ounce is the smaller of the two, so assuming 'imperial must mean bigger' produces a conversion in the wrong direction.
- TSA's 100 milliliter carry-on limit is also frequently misconverted against the commonly cited '3.4 ounces' using a rounded factor, when the precise figure is 3.3814 US fluid ounces, close but not identical to a quick mental conversion.
Frequently Asked Questions
Does this page use the US or imperial fluid ounce?
The US fluid ounce, 29.5735295625 mL. If you're converting a UK product label, use the imperial fluid ounce instead, 28.4131 mL, since it's the smaller of the two despite the name.
Is 100 mL exactly 3.4 fluid ounces for TSA purposes?
Not exactly. The precise figure is 3.3814 US fl oz, and '3.4 ounces' is the commonly cited rounded figure TSA itself uses, close enough that it doesn't cause confusion at the checkpoint.
Why is the imperial fluid ounce smaller than the US one if the imperial gallon is bigger?
The two systems divide their differently sized gallons into a different number of fluid ounces, 128 for the US gallon versus 160 for the imperial gallon, so the larger imperial gallon still ends up split into smaller individual ounces.
How do I convert a children's medicine dose between mL and fl oz?
Multiply the mL dose by 0.0338 to get US fl oz, but always use the syringe or cup that came with the medicine rather than converting by hand, since a small error matters more for medicine than for a recipe.