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Units of Capacity


As we have been learning, everything in maths that relates to the ‘real world’ has units. If an amount represents a real life quantity, it has units attached to it. The units that we use depend on what we are measuring.  

There are some units we need to be familiar with, and know how to convert between. 

LENGTH/DISTANCE mm, cm, m, km
AREA   mm2, cm2, m2, km2 
VOLUME mm3, cm3, m3, km3
WEIGHT (MASS) mg, g, kg, metric tonne 
TIME  sec, mins, hrs, days, weeks, months, years 

Units of capacity

Capacity is the amount of liquid that a container can hold.  Capacity is usually measured using one of the following units: 

  • millilitres (mL
  • litres (L
  • kilolitres (kL
  • megalitres (ML)

You would be used to most of these through previous experiences in the size of your milk container, measuring ingredients when cooking, measuring medicines or even in science experiments you may have done at school. 

                                            $1$1 = $1000$1000 mL

$1$1 kL =    $1000$1000 L     = $1000000$1000000 mL ($1000\times1000$1000×1000)

$1$1 ML = $1000$1000 kL = $1000000$1000000 L = $1000000000$1000000000 mL         Thats about 200 million full teaspoons! 


To move from larger capacity units to smaller capacity units we multiply at each step.

To move from smaller capacity units to larger capacity units we divide at each step.

Do you see some patterns when looking at changing units of capacity? For example, notice that there is a factor of 1000 between each step.  

The prefixes

You see here that we also use the prefixes of milli and kilo again. Remember that the prefix milli means $\frac{1}{1000}$11000 th of something. So we can see here that a millilitre is $\frac{1}{1000}$11000th of a litre, which means that there are $1000$1000 mL in $1$1 litre.  Also the prefix kilomeans $1000$1000 groups of something, so a kilolitre is $1000$1000 litres. 



Question 1

Question: Change $6.732$6.732kL into mL. 

Think: Think about the steps needed to move from kL to mL, (kL -> L  -> mL) and identify the multiplication amounts for each step.  I suggest moving through one step at a time.


First convert to litres:  $6.732\times1000=6732$6.732×1000=6732  L

Then convert to millilitres:  $6732\times1000=6732000$6732×1000=6732000 mL

It really doesn't matter if you think about it like I did, or if you do it differently.  What is important is to keep track of your steps. See how my units changed at each calculation.  

Here is another:

Question 2

Question: Convert $468296$468296 mL into litres

Think: Think about the steps needed to move from ml to litres, (mL -> L ) and identify the division amounts for each step. 

Do: $468296\div1000=468.296$468296÷​1000=468.296 

More Worked Examples


Convert $4920$4920 millilitres to litres.

  1. $4920$4920 millilitres = $\editable{}$ litres.


Convert $1.54$1.54 litres to millilitres.

  1. $1.54$1.54 litres = $\editable{}$ millilitres


Convert $19420$19420 cm3 to litres.

  1. $19420$19420 cm3= $\editable{}$ litres.



Convert between metric units, using whole numbers and commonly used decimals

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