| Centiliters (cL) | Milliliters (mL) |
|---|---|
| 1 Centiliter | 10 mL |
| 2 Centiliters | 20 mL |
| 3 Centiliters | 30 mL |
| 4 Centiliters | 40 mL |
| 5 Centiliters | 50 mL |
| 10 Centiliters | 100 mL |
| 20 Centiliters | 200 mL |
| 25 Centiliters | 250 mL |
| 50 Centiliters | 500 mL |
| 100 Centiliters | 1000 mL |
| Reference | Centiliters (cL) | Milliliters (mL) |
|---|---|---|
| A teaspoon | 0.5 cL | 5 mL |
| A can of soft drink | 33 cL | 330 mL |
| A wine bottle | 75 cL | 750 mL |
| A bathtub | 15000 cL | 150000 mL |
| An Olympic swimming pool | 250000000 cL | 2.5 × 109 mL |
The centilitre is a unit of volume equal to one hundredth of a litre, or ten millilitres. Its symbol is cL, and the lower-case cl is also used. Unlike most centi-prefixed units it has a real commercial life, because it happens to be the size that suits drink labelling, and in several countries it is the form printed on almost every bottle.
Drink containers are its main employment. In France, Belgium, Italy and Spain a wine bottle is labelled 75 cL, a beer 33 or 50 cL, a soft drink 33 cL, and a spirits miniature 5 cL. The same containers carry 750 ml and 330 ml in Britain, Germany and most of the English-speaking world, which is why identical bottles appear to bear different numbers depending on where they were filled.
Bar measures follow the same split. A standard spirit serving is 4 cL in France and 2 or 4 cL in Germany and Austria, while Britain pours 25 or 35 millilitres and the United States uses fluid ounces. European cocktail recipes are written in centilitres throughout, so a classic proportion of six parts to three to one appears as 6 cL, 3 cL and 1 cL, which reads more cleanly than the millilitre equivalents.
There is no legal difference between the forms. European Union labelling rules accept millilitres, centilitres and litres, so the choice is a matter of national typographic habit rather than of regulation. Where centilitres are used, the number on a bottle stays between one and a hundred for every ordinary container size, which is exactly the range a prefix is supposed to deliver.
The unit is also easy to picture. Ten millilitres is two teaspoons, a generous mouthful of water, or the dose measure supplied with a bottle of cough syrup. A tablespoon is one and a half centilitres, an espresso is about three, and a wine glass poured to a standard measure is twelve to fifteen.
Converting between systems needs some care because a centilitre falls between the two customary small measures. It is 0.338 United States fluid ounces and 0.352 imperial fluid ounces, so neither reads as a round number, and drink volumes converted between Europe and North America almost always end up rounded rather than exact.
One centilitre equals 10 millilitres, 0.01 litres, about 0.338 US fluid ounces, or about 0.352 imperial fluid ounces.
The millilitre is a unit of volume equal to one thousandth of a litre, written mL or ml. It is exactly one cubic centimetre. It is the working unit of medicine, cookery, cosmetics and the laboratory, and it is the smallest volume most people handle deliberately in the course of a day.
Medicine relies on it more heavily than on any other unit of volume. Oral liquids are dosed in millilitres, syringes are graduated in them, intravenous fluids are prescribed as so many millilitres per hour, and blood test results are reported per millilitre or per decilitre. The precision matters: a tenfold dosing error in a paediatric prescription is a difference of a single decimal place in this unit.
That is why the household spoon has been driven out of medical instructions. A teaspoon is nominally five millilitres, but real spoons vary from two to nine, so dosing devices are now supplied with liquid medicines and marked in millilitres. Regulators in several countries require the millilitre marking precisely because it removes an ambiguity that spoons cannot.
Cooking outside the United States runs on it. European and Asian recipes give liquids in millilitres and litres rather than in cups, which is more precise because a cup measures volume by an unstandardised container while a millilitre does not. Wine and spirit measures, coffee shot sizes, and the capacity of a baby bottle are all specified in millilitres.
A convenient identity helps in the kitchen and the laboratory alike. One millilitre of water has a mass of one gram, so a recipe or a protocol can move between mass and volume for water-like liquids without a real error. Cosmetics use the same unit throughout, from a five-millilitre sample to a five-hundred-millilitre bottle.
Against United States and imperial measures it converts awkwardly, and the two differ from each other. One millilitre is 0.0338 United States fluid ounces but 0.0352 imperial fluid ounces, so a fluid ounce is about four per cent larger in Britain than in America, and any drink or medicine volume converted between them needs to state which system was meant.
One millilitre equals 1 cubic centimetre, 0.001 litres, about 0.0338 US fluid ounces, or about 0.0352 imperial fluid ounces.