Concept 3 of 7
Capacity: Litres, Millilitres and Decimals
Today's big idea
Capacity is how much a container holds, and 1 L is exactly 1,000 mL.
Millilitres sit to litres exactly as grams sit to kilograms, one thousand apart.
How it works
👀 What's going on?
A water bottle says 1 L. A tube of eye drops says 10 mL. How many of those tiny tubes would it take to fill the bottle?
💡 Here's the trick
Look at the jug above. Capacity is how much a container holds, and 1 L is exactly 1,000 mL. Water gives you a handy bridge too, since 1 mL of it weighs about 1 g.
🪄 How to do it
- 1.Read the marks on the jug above.
- 2.Going from L to mL, multiply by 1000.
- 3.Going from mL to L, divide by 1000.
✍️ Try it
Change 8 L into mL. Then: change 3,750 mL into L.
For L to mL you multiply, so 8 × 1000 = 8,000 mL. For mL to L you divide, so 3,750 ÷ 1000 = 3.75 L.
⚠️ Watch out
You might be thinking a tall glass always holds more than a wide bowl. Height is not capacity. A narrow 300 mL glass still loses to a shallow bowl marked 500 mL.
🌟 Why this matters
Fuel pumps count in L, medicine spoons in mL, and a roof tank in kL. Knowing the 1,000 link tells you at once how many glasses a jug will fill.
Exam tip: Turn every capacity into mL first, then divide to see how many containers fit.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“How many 250 mL glasses can be filled from a 2 L jug?”
- 1
Convert the jug to mL
2 L × 1,000 = 2,000 mL. 🥤
- 2
Same unit on both sides
Now we can divide 2,000 mL by 250 mL.
- 3
Divide
2,000 ÷ 250 = 8
- 4
Answer ✓
8 glasses
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
Step the marker from L to mL. Every rung is ×1000 (or ÷1000 going up).
CAPACITY LADDER · ROUND 1 OF 3
Convert 3 L to mL
Quick check
✅ VERIFICATION
Which container holds the MOST?
⚡ Finish the activity above first to answer.
Keep going!
Up next: Mixed Units
Same unit on both sides means no borrowing surprises.