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MATHEMATICSMeasures & Units
CURRENT TOPICConversions
km
mm
ml
● Master Topic Guide Verified 11+ Curriculum

Units of Measure & Conversions

Master metric unit hierarchy, perimeter/area/volume dimensions, time conversions, and money notation for 11+ exams!

Practice Levels:Warm-UpCore ModePro Mode
Practice Papers
📌

CORE MEASUREMENT TYPES & DEFINITIONS

Understand what each type of measurement represents, its formula, and standard units!

Length

How long something is.

cm · mm · m · km
Perimeter

The total distance around a shape.

a × b
P = 2a + 2b
Area

The space inside a shape.

A = length × width
Volume

The space inside a 3D shape.

cubic units (cm³, m³)
Capacity

The amount a container can hold.

ml, L (millilitres, litres)
Mass

How heavy something is.

g, kg (grams, kilograms)
Time

Measured in seconds, minutes, hours, etc.

s · min · h
Temperature

How hot or cold something is.

°C (degrees Celsius)
1

METRIC UNITS HIERARCHY (LENGTH)

The metric system is based on powers of 10. Move left to make units bigger, move right to make units smaller.

REMEMBER: Using the wrong unit can make your answer completely wrong!
Unitmillimetre (mm)centimetre (cm)metre (m)kilometre (km)
Abbreviationmmcmmkm
How many in next unit?10 mm = 1 cm100 cm = 1 m1,000 m = 1 km—
How many in metre (m)?0.001 m0.01 m1 m1,000 m
How many in kilometre (km)?1,000,000 mm (10⁶ mm)100,000 cm (10⁵ cm)1,000 m (10³ m)1 km
2

PERIMETER, AREA & VOLUME UNITS

Understand dimensions to select the exact right unit exponent every single time!

REMEMBER: Area uses squares (²). Volume uses cubes (³). Perimeter is always 1D length!
PERIMETER1D Length

Distance around the outside of a shape.

Distance around outside
mm millimetre
cm centimetre
m metre
km kilometre
AREA2D Space

Space inside a 2D flat shape.

Space inside flat shape
mm² square millimetre
cm² square centimetre
m² square metre
km² square kilometre
VOLUME & CAPACITY3D Space

Space inside a 3D solid shape or container.

3D Solid Space
mm³ cubic millimetre
cm³ cubic centimetre
m³ cubic metre
L / kL litre (1L = 1000cm³)
3

TIME CONVERSIONS

Know the key time relationships. Essential for 11+ word problems and timetable calculations!

REMEMBER: Read the question carefully — is it asking for minutes, hours, days or weeks?
Seconds → Minutes
60 seconds
= 1 minute
Minutes → Hours
60 minutes
= 1 hour
Hours → Day
24 hours
= 1 day
Days → Week
7 days
= 1 week
Weeks → Month
4 weeks
≈ 1 month
Months → Year
12 months
= 1 year
Standard Year
365 days
= 1 year
Leap Year
366 days
= 1 leap year
Decade
10 years
= 1 decade
Century
100 years
= 1 century
4

MONEY NOTATION

Use correct symbols and format for money. Always include currency symbol (£) and decimal point.

REMEMBER: Don't forget the £ or decimal point. Writing 350 instead of £3.50 is wrong!
FORMATTING RULES
Pence: Use "p"e.g. 75p
Pounds: Use "£"e.g. £3
Decimal notation (show pence)e.g. £3.75 (= £3 and 75p)
No space between £ and number
Correct: £3.50
Not: £ 3.50
COMMON EXAMPLES
250p= £2.50
£1.20= £1 and 20p
99p= £0.99
£5.00= £5
💡 Always write pence with 2 decimal places when using £!

ALWAYS CHECK THE QUESTION!

  • Check what unit the answer needs to be in.
  • Look for unit clues in the question (cm, m, km, L, g, etc.).
  • If you don't read to the end, you could lose easy marks!
TOP MARKS FORMULA
RIGHT UNIT = RIGHT ANSWER
INTERACTIVE UNIT CONVERSION QUIZ
5 km = ___ m

Multiply by 1,000 (1km = 1000m)

350 cm = ___ m

Divide by 100 (100cm = 1m)

4500 ml = ___ L

Divide by 1,000 (1L = 1000ml)

450p = £___

Divide by 100 to get pounds

3 hours = ___ minutes

Multiply 3 × 60 minutes

2.5 kg = ___ g

Multiply 2.5 × 1,000

🚀 Ready to Test Your Knowledge?

Take our graded 11+ Units of Measure assessment now!