Converting metric units

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In order to access this I need to be confident with:

Multiplying and dividing by powers of 10

Decimals Place value

This topic is relevant for:

GCSE Maths Ratio and Proportion Units Of Measurement

Converting Metric Units

Here we will learn about converting metric units, including metric units of length, metric units of mass and metric units of capacity (volume).

There are also converting metric units worksheets based on Edexcel, AQA and OCR exam questions, along with further guidance on where to go next if you’re still stuck.

What is converting metric units?

Converting metric units is being able to convert between different metric units of length, mass or volume.

To do this we need to know what the metric units are and their conversion factors.

We can use prefixes to make these metric units bigger and smaller.

The main ones used are kilo, centi and milli:

What is converting metric units?

Metric units of length

The SI unit (international system of units) of length is the metre $(m)$ .

For length we mostly use kilometres $(km)$ , metres $(m)$ , centimetres $(cm)$ and millimetres $(mm)$ .

1 \ km=1000 \ m

1 \ m= 100 \ cm

1 \ m= 1000 \ mm

1 \ cm= 10 \ mm

E.g.

Covert $7 \ m$ to centimetres

7 \times 100=700

So, $7 \ m=700 \ cm$

Metric units of mass

The metric system for mass is based around grams $(g)$ .

For mass we mostly use tonnes $(t)$ , kilograms $(kg)$ , and grams $(g)$ .

1 \ tonne=1000 \ kg

1 \ kg= 1000 \ g

E.g.

Covert $4 \ kg$ to centimto grams

4 \times 1000=4000

So, $4 \ kg=4000 \ g$

Metric units of capacity (volume)

The SI unit The metric system for capacity is based on litres $(l)$ .

For volume we mostly use litres $(l)$ , centilites $(cl)$ , and millilitres $(ml)$ .

1 \ litre=1000 \ ml

1 \ litre= 100 \ cl

1 \ cl= 10 \ ml

We also need to be aware that:

1 \ litre=1000 \ cm^3

E.g.

Covert $6000 \ ml$ to litres

6000 \div 1000 = 6

So, $6000 \ ml=6 \ l$

How to convert metric units

In order to convert metric units:

Find the unit conversion.
Multiply or divide.
Write the answer.

How to convert metric units

Converting metric units worksheet

Get your free converting metric units worksheet of 20+ questions and answers. Includes reasoning and applied questions.

DOWNLOAD FREE

Converting metric units worksheet

Get your free converting metric units worksheet of 20+ questions and answers. Includes reasoning and applied questions.

DOWNLOAD FREE

Related lessons on units of measurement

Converting metric units is part of our series of lessons to support revision on units of measurement. You may find it helpful to start with the main units of measurement lesson for a summary of what to expect, or use the step by step guides below for further detail on individual topics. Other lessons in this series include:

Converting metric units examples

Example 1: converting length

Convert $3.2 \ m$ to $cm$

Find the unit conversion.

1 \ m=100 \ cm

2Multiply or divide.

As we are going from larger units to smaller units we multiply.

3.2 \times 100=320

3Write the answer.

3.2 \ m=320 \ cm

Example 2: converting length

Convert $780 \ mm$ to $cm$

Find the unit conversion.

1 \ cm=10 \ mm

Multiply or divide.

As we are going from smaller units to larger units we divide.

$780 \div 10=78$

Write the answer.

780 \ mm=78 \ cm

Example 3: converting mass

Convert $12.5 \ kg$ to $g$

Find the unit conversion.

1 \ kg=1000 \ g

Multiply or divide.

As we are going from larger units to smaller units we multiply.

$12.5 \times 1000=12 \ 500$

Write the answer.

12.5 \ kg=12 \ 500 \ g

Example 4: converting mass

Convert $3800 \ g$ to $kg$

Find the unit conversion.

1 \ kg=1000 \ g

Multiply or divide.

As we are going from smaller units to larger units we divide.

$3800\div 1000=3.8$

Write the answer.

3800 \ g=3.8 \ kg

Example 5: converting capacity

Convert $7.1 \ l$ to $ml$

Find the unit conversion.

1 \ l=1000 \ ml

Multiply or divide.

As we are going from larger units to smaller units we multiply.

$7.1 \times 1000=7100$

Write the answer.

7.1 \ l=7100 \ ml

Example 6: converting capacity

Convert $750 \ ml$ to $l$

Find the unit conversion.

1 \ l=1000 \ ml

Multiply or divide.

As we are going from smaller units to larger units we divide.

$750 \div 1000=0.75$

Write the answer.

750 \ ml=0.75 \ l

Example 7: converting capacity

Convert $6.8 \ l$ to $cm^3$

Find the unit conversion.

1 \ l=1000 \ cm^3

Multiply or divide.

As we are going from larger units to smaller units we multiply.

$6.8 \times 1000=6800$

Write the answer.

6.8 \ l=6800 \ cm^3

Common misconceptions

Multiply or divide?

Remember:

If you are going from larger units to smaller units – multiply
If you are going from smaller units to larger units – divide

Practice converting metric units questions

39 \ m

3.9 \ m

390 \ m

0.39 \ m

Converting centimetres to metres we divide by $100$ .

390\div 100=3.9 \ m

5 \ 700 \ mm

5.7 \ mm

570 \ mm

57 \ 000 \ mm

Converting centimetres to millimetres we multiply by $10$ .

57\times 10=570 \ cm

810 \ kg

81 \ kg

8.1 \ kg

8100 \ kg

Converting grams to kilograms we divide by $1000$ .

81\ 000\div 1000=81 \ kg

6300 \ tonnes

6.3 \ tonnes

63 \ tonnes

0.63 \ tonnes

Converting kilograms to tonnes we divide by $1000$ .

630\div 1000=0.63 \ tonnes

4800 \ ml

480 \ ml

48 \ ml

48 \ 000 \ ml

Converting litres to millilitres we multiply by $1000$ .

4.8\times 1000=4800 \ ml

56 \ l

0.56 \ l

5.6 \ l

0.056 \ l

Converting millilitres to litres we divide by $1000$ .

560\div 1000=0.56 \ l

Converting metric units GCSE questions

1. Write $376 \ cm$ in metres.

(1 mark)

Show answer

376\div 100=3.76

(1)

2. Here is a signpost

Converting metric units GCSE question 2

How far apart are the Town Centre and the Park?

Give your answer in kilometres.

(3 marks)

Show answer

650\div 1000 = 0.65

Converting distance to km

(1)

3.5+0.65

Adding the two distances

(1)

4.15 \ km

(1)

3. A bottle contains $1.75$ litres of lemonade.

A can contains $330 \ ml$ of lemonade.

Phil has $2$ bottles of lemonade and $6$ cans of lemonade.

How much lemonade does he have in total?

Give your answer in millilitres.

(3 marks)

Show answer

1.75\times 1000=1750

Converting capacity to millilitres

(1)

2\times 1750+6\times 330

For finding the total

(1)

5480 \ ml

(1)

4. $4$ tins of soup have a mass of $1.8$ kg.

$3$ tins of soup and $2$ packets of soup have a mass of $1420 \ g.$

Find the mass of $7$ tins of soup and $5$ packets of soup.

Give your answer in kilograms.

(5 marks)

Show answer

1.8\div4=0.45 \ kg

Finding the mass of one tin

(1)

1420\div 1000=1.42 \ kg

Converting mass to kg

(1)

(1.42-3\times 0.45)\div 2=0.035

(1)

7\times 0.45+5\times 0.035

(1)

3.325 \ kg

(1)

Learning checklist

You have now learned how to:

Convert metric units of length

Convert metric units of mass

Convert metric units of capacity (volume)

The next lessons are

Still stuck?

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