What is litre?
The litre is a metric unit of volume equal to one cubic decimetre. It is widely used for measuring liquid quantities in cooking, beverages, fuel, and laboratory work across metric countries.
Real-world uses
Litres are the global standard for beverage volumes, fuel tank capacities, engine displacement, and liquid medications. Water intake recommendations are given in litres (about 2 L/day), and swimming pools are measured in thousands of litres.
History
The litre was originally defined in 1795 as one cubic decimetre. In 1901 it was redefined based on the mass of water, creating a tiny discrepancy with the cubic decimetre. In 1964, the original definition (1 L = 1 dm³ exactly) was restored.
Common mistakes
Confusing litres with liters (both are correct—"litre" is the international spelling, "liter" is American). Also, assuming 1 litre of any liquid weighs 1 kg; this is only true for water at 4°C.
What is millilitre?
A millilitre is a metric unit of volume equal to one thousandth of a litre. It is commonly used in medicine, cooking, laboratory measurements, and the labelling of food and beverage products.
Real-world uses
Millilitres are used for medication dosages (cough syrup, injectable solutions), cooking measurements, cosmetic product volumes, and laboratory reagent quantities. A standard medical syringe is graduated in mL, and espresso shots are typically 25–30 mL.
History
The millilitre emerged naturally from the litre with metric prefix conventions. It became essential in medicine and laboratory science where precise small-volume measurements are critical. In medical contexts, "cc" (cubic centimetre) was long used interchangeably with mL.
Common mistakes
Confusing millilitres with cubic centimetres—they are numerically equal (1 mL = 1 cm³) but conceptually different units. Also, mixing up mL with mg; one is volume, the other is mass.
When is this conversion used?
Fuel economy, beverage volumes, and liquid measurements frequently require converting between litres and US gallons, especially for automotive and cooking contexts across different markets.
Worked examples
1 litre = 1,000 millilitre
1 millilitre = 0.001 litre
How to convert litre to millilitre
To convert litre to millilitre, multiply the value by 1,000.
To convert millilitre back to litre, multiply by 0.001.
Measurement standards
The cubic metre is the SI derived unit of volume. The litre, equal to exactly one cubic decimetre (0.001 m³), is accepted by the BIPM for use alongside SI units. Both the lowercase "l" and uppercase "L" are approved symbols for the litre.
Did you know?
An Olympic swimming pool holds 2,500 cubic metres of water — about 2.5 million litres. The Amazon River discharges roughly 209,000 cubic metres per second, enough to fill 84 Olympic pools every single second.
Quick reference: litre to millilitre
| litre | millilitre |
|---|---|
| 0.1 | 100 |
| 0.5 | 500 |
| 1 | 1,000 |
| 2 | 2,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 250 | 250,000 |
| 500 | 500,000 |
| 1,000 | 1,000,000 |
Common values
| litre | millilitre | |
|---|---|---|
| A teaspoon | 0.005 litre | 5 millilitre |
| A cup of coffee | 0.25 litre | 250 millilitre |
| A water bottle | 0.5 litre | 500 millilitre |
| A bathtub | 300 litre | 300,000 millilitre |
| A swimming pool (Olympic) | 2,500,000 litre | 2.500000e+09 millilitre |