Convert units of capacity
Theory
One litre is \(1000\) millilitres. To change to a smaller unit, multiply by \(1000\); to change to a larger unit, divide by \(1000\).
A millilitre (mL), a litre (L) and a kilolitre (kL) are metric units of capacity — how much a container holds. The prefix milli means a thousandth and kilo means a thousand, so \(1\text{ L} = 1000\text{ mL}\) and \(1\text{ kL} = 1000\text{ L}\).
To change to a smaller unit (such as L to mL), multiply by \(1000\). The unit is smaller, so it takes more of them and the number gets bigger.
To change to a larger unit (such as mL to L), divide by \(1000\). The unit is larger, so fewer are needed and the number gets smaller.
Every step multiplies or divides by \(1000\).
| Litres | Millilitres |
|---|---|
| \(1\) L | \(1000\) mL |
| \(2\) L | \(2000\) mL |
| \(2.5\) L | \(2500\) mL |
| \(0.5\) L | \(500\) mL |
| \(1\) L \(500\) mL | \(1500\) mL |
And for the larger unit: \(1\text{ kL} = 1000\text{ L}\), so \(3\text{ kL} = 3000\text{ L}\).
Converting units of capacity
- Decide the direction: which unit are you changing to?
- To a smaller unit (L to mL, or kL to L), multiply by \(1000\).
- To a larger unit (mL to L, or L to kL), divide by \(1000\).
- To compare or order capacities, change them all to the same unit first, then compare the numbers.
- Check: to a smaller unit the number grows; to a larger unit it shrinks.
A millilitre is smaller, so multiply by \(1000\).
| \(7 \times 1000\) | \(=\) | \(7000\) |
So \(7\text{ L} = 7000\) mL.
A litre is larger, so divide by \(1000\).
| \(2600 \div 1000\) | \(=\) | \(2.6\) |
So \(2600\text{ mL} = 2.6\) L.
A litre is smaller, so multiply by \(1000\).
| \(6 \times 1000\) | \(=\) | \(6000\) |
So \(6\text{ kL} = 6000\) L.
Change the litres, then add the extra.
| \(2 \times 1000\) | \(=\) | \(2000\) |
| \(2000 + 350\) | \(=\) | \(2350\) |
So \(2\text{ L }350\text{ mL} = 2350\) mL.
Common pitfalls
Frequently asked questions
How many millilitres are in a litre?
\(1000\). The prefix milli means a thousandth, so \(1\text{ L} = 1000\text{ mL}\).
How do I change litres to millilitres?
Multiply by \(1000\), because a millilitre is smaller. For example \(3\text{ L} = 3 \times 1000 = 3000\) mL.
How do I change millilitres to litres?
Divide by \(1000\), because a litre is larger. For example \(5000\text{ mL} = 5000 \div 1000 = 5\) L.
What is a kilolitre?
A kilolitre (kL) is the next unit up: \(1\text{ kL} = 1000\text{ L}\). To change kilolitres to litres, multiply by \(1000\), so \(3\text{ kL} = 3000\) L.
How do I compare a capacity in litres with one in millilitres?
Change them to the same unit first, then compare the numbers. For example \(1.5\) L is \(1500\) mL, which is more than \(1200\) mL.