Fluid Oz to Millilitres Converter
16 fl oz × 29.5735 = 473.2 ml
One US fluid oz is 29.5735 millilitres. To convert fluid oz to millilitres, multiply by 29.5735; to go the other way, divide millilitres by 29.5735. So 8 fl oz is 236.59 mL, 12 fl oz is 355 mL, and 16.9 fl oz is 500 mL. The converter above does this for any value, in either direction, and rounds sensibly for kitchen and label use.
Two details trip people up. The imperial (UK) fluid oz is a different size, 28.4131 mL, so a British recipe calling for 10 fl oz means 284 mL, not 296 mL. And the fluid oz is a unit of volume, not weight; it is not the same as the oz (oz) used on a kitchen scale. This page covers both, plus the reason your shampoo bottle and its nutrition-style panel appear to disagree.
How many millilitres are in a fluid oz?
There are 29.5735 millilitres in one US fluid oz. The full defined value is 29.5735295625 mL exactly, because the US gallon is fixed at 3.785411784 litres and a fluid oz is 1/128 of that gallon. The figure is exact by definition rather than measured, so 29.5735 mL is a rounding of a precise number, not an approximation of a fuzzy one.
The imperial fluid oz used in the UK, Ireland, and older Commonwealth recipes is 28.4131 mL, about 4% smaller. The gap matters at volume: 20 imperial fl oz is 568 mL (one UK pint), while 20 US fl oz is 591 mL. Check the source of your number before you convert it.
The formula
Millilitres = fluid oz × 29.5735. Reverse it by dividing: fluid oz = millilitres ÷ 29.5735. A useful mental shortcut is that 30 mL is close enough to 1 fl oz for cooking, so a 12 fl oz can is roughly 360 mL, near the true 355 mL. For anything that has to be right, use the full factor. Within the US system the ratios are clean: 1 fl oz = 2 tbsp = 6 tsp, and 8 fl oz = 1 US cup = 236.59 mL.
- Confirm which oz you have. A US fluid oz is 29.5735 mL; an imperial (UK) fluid oz is 28.4131 mL. American recipes and product labels use the US oz.
- Multiply the number of fluid oz by 29.5735. For 16 fl oz: 16 × 29.5735 = 473.18 mL.
- Round for the job in hand. Kitchen work tolerates the nearest 5 mL (473.18 mL becomes 475 mL); pharmacy, lab, and label work should keep two decimals.
What is a fluid oz?
A fluid oz is a unit of volume in the US customary and imperial systems. It measures how much space a liquid occupies, which is why it appears on drink cans, perfume boxes, and medicine cups. It is written "fl oz" precisely to separate it from "oz", the avoirdupois oz of weight (28.3495 g). Those two units are unrelated: 8 fl oz of water weighs about 8 oz, but 8 fl oz of honey weighs far more, and 8 fl oz of oil weighs less.
The US fluid oz descends from the wine gallon of 1707; the imperial oz was redefined in 1824 around the volume of water weighing one avoirdupois oz. That is the whole reason the two sizes differ. Both are now defined against the metric system, the US oz via the litre-based gallon, the imperial oz as exactly 28.4130625 mL, so every fluid oz in use today rests on a millilitre value underneath.
What is a millilitre?
A millilitre is one thousandth of a litre, and one millilitre is exactly one cubic centimetre (cc). It is the standard small-volume unit almost everywhere outside the United States, and it is the unit medicine uses worldwide, dosing syringes are marked in mL even in the US, because decimal arithmetic causes fewer errors than fractions of an oz.
The correct symbol is "mL" with a capital L, though "ml" is widely accepted and means the same thing. The capital exists because a lowercase "l" is easy to misread as a digit 1 in handwriting and on labels. Multiples scale by tens with no conversion factors to memorise: 1000 mL = 1 L, 500 mL = 0.5 L (16.9 fl oz), 250 mL = 0.25 L (8.45 fl oz).
Why nutrition labels say 30 mL when the real answer is 29.5735 mL
Pick up a 12 fl oz drink can and it will also print 355 mL. That is honest customary maths: 12 × 29.5735 = 354.88, rounded to 355 mL. Now read the nutrition panel on the same can. It may list a serving of "12 fl oz (360 mL)". The two numbers on one container disagree by 5 mL, and neither is a misprint.
The explanation is that the US FDA defines a separate labeling fluid oz for nutrition panels, set at exactly 30 mL. Title 21 of the Code of Federal Regulations tells manufacturers to express fluid measures on the Nutrition Facts panel using that round figure, so a serving stated as 1 fl oz becomes 30 mL, 8 fl oz becomes 240 mL, and 12 fl oz becomes 360 mL. The net-quantity statement on the front of the pack follows the real customary definition instead, which is why it says 355 mL. Same liquid, two different rounding rules mandated for two different parts of the label.
This is a packaging convention, not a second physical unit. Nothing about the oz itself changes, the FDA simply chose a round number so serving sizes stay comparable across products and consumers are not asked to divide by 29.5735. When you convert for a recipe, a dose, or a cargo manifest, use 29.5735 mL. Use 30 mL only when you are reproducing what a nutrition panel prints, and never treat the 5 mL gap on a can as evidence that someone got the arithmetic wrong.
Fluid oz to millilitres conversion table
Values use the US fluid oz (29.5735 mL). For imperial (UK) fluid oz, multiply by 28.4131 instead.
| Fluid oz (US) | Milliliters |
|---|---|
| 1 | 29.57 |
| 1.7 | 50.28 |
| 2 | 59.15 |
| 2.5 | 73.93 |
| 3 | 88.72 |
| 3.4 | 100.6 |
| 4 | 118.3 |
| 5 | 147.9 |
| 6 | 177.4 |
| 8 | 236.6 |
| 10 | 295.7 |
| 12 | 354.9 |
| 16 | 473.2 |
| 20 | 591.5 |
| 24 | 709.8 |
| 32 | 946.4 |
| 40 | 1,183 |
1 fl oz = 29.5735 ml
Popular fluid oz and millilitre conversions
Frequently asked questions
No. One US fluid oz is 29.5735 mL, which is about 1.4% less than 30 mL. The 30 mL figure comes from the FDA's labeling fluid oz, used only on Nutrition Facts panels, and from kitchen rounding. For a single oz the 0.43 mL error is harmless; across 32 fl oz it grows to about 13.7 mL.
Because 100 mL is 3.38 US fl oz, and manufacturers round up to 3.4 oz on the label. The airport rule is written in millilitres, 100 mL per container, so a bottle marked 3.4 fl oz is exactly at the limit, not over it. A bottle marked 3.5 fl oz (103 mL) can be refused.
Both are understood, but mL with a capital L is the preferred form. The uppercase L was approved to prevent a lowercase l being misread as the digit 1, which matters on medicine labels. Litre-based units are the only SI units allowed this exception, since the unit is not named after a person.
A standard US shot is 1.5 fl oz, which is 44.36 mL, usually called 44 mL or rounded to 45 mL. A UK single measure is defined in metric terms at 25 mL or 35 mL depending on the venue, and a double is 50 mL. Do not convert a US shot into a UK measure and expect the same pour.
Because 12 × 29.5735 = 354.88 mL, which rounds to 355 mL. That is the true customary conversion, printed as the net quantity on the front of the can. If the nutrition panel on the same can implies 360 mL, that is the FDA labeling oz of 30 mL, a separate rounding rule for that panel only.
3.4 US fl oz is 100.55 mL. Products sold at exactly 100 mL are labelled 3.4 fl oz because 100 mL converts to 3.38 fl oz and 3.4 is the nearest tenth. In skincare, 1.7 fl oz on a bottle likewise means the metric 50 mL size, not 50.3 mL.
8 US fl oz is 236.59 mL, and that is also one US cup. If the recipe is British, 8 imperial fl oz is 227.30 mL. Note this is a volume of water, not a weight, 8 fl oz and 8 oz on a scale are different measurements that only coincide for water by accident of history.
No. A US fluid oz is 29.5735 mL and an imperial (UK) fluid oz is 28.4131 mL, so the US oz is about 4% larger. Confusingly, a UK pint holds 20 fl oz (568 mL) while a US pint holds 16 fl oz (473 mL), making the UK pint the bigger of the two despite its smaller oz.
A standard wine bottle is 750 mL, which converts to 25.36 US fl oz and is usually printed as 25.4 fl oz. The 750 mL size is the metric standard set for wine trade, so the oz figure on a US label is a conversion of the metric bottle, not the other way round.
Divide the millilitres by 29.5735 for US fluid oz, or by 28.4131 for imperial. So 500 mL ÷ 29.5735 = 16.91 fl oz, which is why a half-litre water bottle is sold as 16.9 fl oz in the United States. A quick estimate is to divide by 30 and add about 1.5%.