The liter is a unit of measure in the metric system that expresses the capacity or volume of something, usually a liquid. This unit is widely used and common. It can be seen on bottles of water, milk and all other liquid products. By a calculation, it is possible to know the volume in liters of a container with only the dimensions of the latter. Sometimes the capacity of an object is given in another unit such as gallons or hectoliters. The conversion is not complicated. Depending on the unit, a multiplication or a division will allow to know the volume in liters.
Steps
Method 1 of 3: Give the volume in liters with the dimensions of the container
Step 1. Convert the dimensions to centimeters
If your container is given with measurements in inches, meters, feet or some other unit of measurement, you will have to convert them to centimeters to facilitate the calculation of the capacity of the object and thus obtain a result in liters in the end..
 Know that 1 m is equal to 100 cm. Suddenly, a cube whose sides are 2.5 m has sides of 250 cm in centimeters, 2.5 X 100 = 250.
 Note that 1 inch equals 2.54cm. For a 5 inch cube, the length in centimeter is 12.7 cm, 5 X 2.54 = 12.7.
 The value of 1 foot is equal to 30.48 cm. So a 3foot cubic container will have a centimeter rating of 91.44 cm, 3 X 30, 48 = 91, 44.
Step 2. Determine the volume of a container
To calculate the volume of an object, it is more or less easy depending on the shape of the latter. The calculation differs depending on the form. The calculation of the volume, for example for a cube is the Volume = Length X Width X Height. Note that the volume of a container is expressed in cubic units, like cubic centimeters (cm3 { displaystyle cm ^ {3}}
).

Prenons un exemple avec un aquarium qui fait 40, 64 cm de long sur 25, 4 cm de largeur et 20, 32 cm de hauteur. Pour calculer le volume, vous devez faire ainsi:
Volume = Longueur X Largeur X Hauteur
Volume = 40, 64 X 25, 4 X 20, 32
Volume = 20 975 cm3{displaystyle cm^{3}}
Step 3. Go from cubic centimeters to liters
To convert cubic centimeters into liters, you need to take into account the following conversion rate: 1 L = 1000 cm3 { displaystyle cm ^ {3}}
. Ainsi pour obtenir le volume en litre, vous devez diviser votre volume en centimètre cube par 1 000.
 Ainsi pour calculer le volume de l'aquarium, dont la valeur en centimètre cube est de 20 975, on devra faire 20 975 ÷{displaystyle \div }
1 000 = 20, 975. Le volume donc d'un aquarium qui mesure 40, 64 cm de long sur 25, 4 cm de large et d'une hauteur de 20, 32 cm de hauteur a un volume de 20, 975 L.
Méthode 2 sur 3: Convertir des litres dans d'autres unités métriques
Step 1. Go from milliliters to liters
Know that one liter is equal to one thousand milliliters. So, to convert milliliters into liters, you have to divide the milliliters by the thousand to get the value in liters.
 For example, a carton of milk of 1890 mL to know its volume in liters, you have to 1,890 mL ÷ { displaystyle \ div}
1 000 = 1, 89 L. La brique contient 1, 89 L de lait.
Step 2. Change centiliters to liters
Note that one hundred centiliters is the equivalent of one liter. If you want to convert centiliters to liters, you will need to divide by hundred.
 Starting with the example of a carton of milk that makes 189 cL, you have to 189 cL ÷ { displaystyle \ div}
100 = 1, 89 L et ainsi la brique a un volume de lait de 1, 89 L.
Step 3. Convert deciliters to liters
You will find ten deciliters in a liter and therefore to pass a given volume in deciliter in liter, you will have to divide by ten.
 If you have a brick that contains 18.9 dL of milk and you want to know its volume in liters, you need to do the following calculation: 18, 9 dL ÷ { displaystyle \ div}
10 = 1, 89 L.
Step 4. Go from kiloliter to liter
You will get one thousand liters in one kiloliter. If you need to convert kiloliters to liters, multiply your volume in kiloliter by a thousand.
 Your pool has a volume of 240 kL and you are interested in knowing its volume in liters. You must therefore perform an operation which is as follows: 240 kL X 1,000 = 240,000 L.
Step 5. Convert hectoliters to liters
The volume of a container containing one hundred liters has a volume equal to one hectolitre. So, if you want to convert hectoliters into liters you will have to multiply your hectoliters by one hundred to know the volume in liters.
 For example, for a 2,400 hL swimming pool for which you want to know the volume in liters, you will have to do the following calculation: 2,400 hL X 100 = 240,000 L.
Step 6. Convert decaliters to liters
Note that a container that holds ten liters has a volume of one decaliter, which will lead you to multiply the number of decaliters by ten to find a volume in liters.
 For a pool with a volume of 24,000 daL, if you want to know its volume in liters, do the following: 24,000 daL X 10 = 240,000 L.
Method 3 of 3: Change liters to US units of measure
Step 1. Go from US fluid ounces to liters
For a container of 33, 81 ounces of a liquid (fl oz) you have a liter and therefore if you want to know in liters the volume of a container containing a volume in ounces, you will have to divide by 33, 81 the value in ounces of liquid.
 For example a 128 fl oz carton of milk, to know its volume in liters, you will need to perform the following calculation: 128 fl oz ÷ { displaystyle \ div}
33, 81 = 3, 786 L.
Step 2. Change the unit from one volume to liquid US quart by liters
If you have a container that contains a liquid of 2, 113 pints (fl pt), its correspondence in liter is one liter and therefore to convert a volume into a pint, it will be necessary to divide by 2, 113 to obtain a volume in liter.
 For example, if you ordered a pitcher of beer that has a volume of 8 fl pt. To know its value in liters, do this calculation: 8 fl pt ÷ { displaystyle \ div}
2, 113 = 3, 786 L.
Step 3. Convert US quarts to liters
For a liter of a liquid, you have in equivalence 1.057 quarts and therefore to obtain a liter you will have to divide by 1.057 your value given in American quart.
 With a pitcher with a capacity of four quarters, if you want to know the volume in liters, you will have to do the following calculation: 4 qt ÷ { displaystyle \ div}
1, 057 = 3, 784 L.
Step 4. Convert US gallons to liters
Be aware that 3, 7854 L is the equivalent of a gallon (gal). So, if you want to go from gallons to liters you will have to multiply your gallons by 3, 7854 to know the volume in liters.
 Using an aquarium with a volume of 120 gallons as an example to find out how many liters the aquarium contains, the following calculation must be made: 120 gal X 3, 7854 = 454, 248 L.