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measurement

Converting millilitres and litres

Use 1,000 millilitres in 1 litre to convert.

Quick answer

1,000 millilitres (ml) equals 1 litre (L). To convert millilitres to litres, divide by 1,000. To convert litres to millilitres, multiply by 1,000.

Learning outcome

By the end of this page, you will be able to convert between millilitres and litres using simple multiplication and division. Success signs:
  • You can say how many millilitres are in 1 litre
  • You can convert 2,500 ml to litres
  • You can convert 3.5 litres to millilitres
  • You can solve real-life problems with millilitres and litres

Why this matters

Understanding millilitres and litres helps you measure liquids in cooking, drinks, medicine, and science. You’ll use this skill when:
  • Helping in the kitchen with recipes
  • Buying drinks or water
  • Watering plants or filling a fish tank
  • Doing science experiments
  • Playing games that involve measuring

How it works

Converting between millilitres and litres is simple because they are related by a factor of 1,000.
  1. 1 litre = 1,000 millilitres
  2. To change from millilitres to litres, divide by 1,000
  3. To change from litres to millilitres, multiply by 1,000
Think of it like this:
  • 1,000 small cups = 1 big jug
  • 1,000 tiny drops = 1 big splash

Examples you can see

Let’s look at some examples to make it clearer. Example 1: Converting millilitres to litres You have 3,000 ml of water. How many litres is that?
  • 3,000 ml ÷ 1,000 = 3 litres
Example 2: Converting litres to millilitres You have 2.5 litres of juice. How many millilitres is that?
  • 2.5 litres × 1,000 = 2,500 ml
Example 3: Real-world example Imagine you are filling a water bottle that holds 500 ml. How many of these bottles would you need to fill a 1-litre jug?
  • 1 litre = 1,000 ml
  • 1,000 ml ÷ 500 ml = 2 bottles

Try it as a mini adventure

The Great Water Challenge You are a scientist in a lab trying to mix the perfect potion. You have two containers:
  • Container A has 750 ml of liquid
  • Container B has 1.25 litres of liquid
You need to know the total amount in litres to record it in your lab book.
  1. First, convert 750 ml to litres: 750 ÷ 1,000 = 0.75 litres
  2. Then, add the amounts: 0.75 + 1.25 = 2 litres
Challenge: How many 250 ml cups can you fill from 1 litre of water?
  • 1 litre = 1,000 ml
  • 1,000 ml ÷ 250 ml = 4 cups

Common mistakes

  • Mistake: Thinking 1,000 ml = 10 litres
  • Why it happens: Confusing the direction of conversion
  • Fix: Remember: 1,000 ml = 1 litre. So 10 litres = 10,000 ml
  • Mistake: Forgetting to move the decimal point when dividing by 1,000
  • Why it happens: Not thinking about place value
  • Fix: Count three decimal places to the left when dividing by 1,000
  • Mistake: Multiplying by 100 instead of 1,000
  • Why it happens: Misremembering the relationship
  • Fix: Always remember: 1 litre = 1,000 ml

Parent and carer guide

Here are 5 ways to help your child learn this skill:
  1. Use everyday objects: Show 1,000 ml of water in a large jug and 1 litre in a small bottle to compare
  2. Practice with cooking: When baking, let your child measure ingredients in ml and litres
  3. Play conversion games: Ask: “How many 250 ml cups are in 1 litre?”
  4. Use a calculator: For bigger numbers, let them check their answers
  5. Be patient: It takes time to get used to the idea of 1,000 units in 1 big unit
What to say:
  • “Let’s think about how many small cups fit into one big jug.”
  • “Can you show me 1,000 ml with your hands?”
  • “What happens when we divide by 1,000?”
What not to worry about:
  • They may get confused at first – that’s normal
  • They might make a mistake – that’s how we learn
  • They might need to count by 1,000s to understand the pattern

Practice questions

  1. Convert 500 ml to litres
  2. Convert 4.7 litres to millilitres
  3. How many 100 ml cups can you fill from 1 litre?
  4. Convert 2,300 ml to litres
  5. How many 500 ml bottles can you fill from 2 litres?
Answers:
  1. 500 ml = 0.5 litres
  2. 4.7 litres = 4,700 ml
  3. 10 cups
  4. 2.3 litres
  5. 4 bottles

FAQ

What is the difference between millilitres and litres?

Millilitres are a smaller unit of measurement for liquids. One litre is equal to 1,000 millilitres.

How do I know if I should multiply or divide?

If you're going from millilitres to litres, divide by 1,000. If you're going from litres to millilitres, multiply by 1,000.

Can I use decimals when converting?

Yes! For example, 500 ml = 0.5 litres. You can use decimals when the number isn't a whole number.

Why is it important to learn this?

Knowing how to convert millilitres and litres helps you measure drinks, cooking ingredients, and medicines correctly. It's useful in science, cooking, and everyday life.

What if I forget the relationship?

Remember: 1 litre = 1,000 ml. You can also use a simple trick: 1,000 ml = 1 L. That's it!