Improve Tuition · Grade 2 · Metric Conversions
Lesson · Practice · Steps

Metric Conversions

Convert between units. Bigger unit = smaller number. Smaller unit = bigger number.

The six facts you need

Every metric conversion uses one of these. You don't need to remember anything else.

1 · Length10 mm = 1 cm · 100 cm = 1 m · 1000 m = 1 km.
2 · Mass1000 g = 1 kg.
3 · Capacity1000 ml = 1 l.
4 · Going to bigger unitsDIVIDE. Smaller-to-bigger unit means the number gets smaller.
5 · Going to smaller unitsMULTIPLY. Bigger-to-smaller unit means the number gets bigger.
6 · Multi-stepCombine: mm to m in one go = ÷ 1000. m to mm = × 1000.

Worked example 1 - mm to cm

Convert 250 mm to cm.

250mm25cm÷ 10
  1. Read it. Convert 250 mm to cm.
  2. The fact. 10 mm = 1 cm. mm to cm (bigger unit): ÷ 10.
  3. 250 ÷ 10 = 25.
  4. So 250 mm = 25 cm.
Answer: 25 cm
Watch outGoing to a BIGGER unit means the NUMBER gets smaller. Divide, don’t multiply.

Worked example 2 - cm to mm

Convert 3.5 cm to mm.

3.5cm35mm× 10
  1. Read it. Convert 3.5 cm to mm.
  2. The fact. 1 cm = 10 mm. cm to mm (smaller unit): × 10.
  3. 3.5 × 10 = 35.
  4. So 3.5 cm = 35 mm.
Answer: 35 mm
Watch outGoing to a SMALLER unit means the NUMBER gets bigger. Multiply.

Worked example 3 - cm to m

Convert 450 cm to m.

450cm4.5m÷ 100
  1. Read it. Convert 450 cm to m.
  2. The fact. 100 cm = 1 m. cm to m: ÷ 100.
  3. 450 ÷ 100 = 4.5.
  4. So 450 cm = 4.5 m.
Answer: 4.5 m
Watch outDivide by 100, not 10. Different pair of units, different power.

Worked example 4 - m to cm

Convert 2.7 m to cm.

2.7m270cm× 100
  1. Read it. Convert 2.7 m to cm.
  2. The fact. 1 m = 100 cm. m to cm: × 100.
  3. 2.7 × 100 = 270.
  4. So 2.7 m = 270 cm.
Answer: 270 cm
Watch outTo multiply by 100, move the decimal point 2 places to the right.

Worked example 5 - m to km

Convert 3000 m to km.

3000m3km÷ 1000
  1. Read it. Convert 3000 m to km.
  2. The fact. 1000 m = 1 km. m to km: ÷ 1000.
  3. 3000 ÷ 1000 = 3.
  4. So 3000 m = 3 km.
Answer: 3 km
Watch outTo divide by 1000, move the decimal point 3 places to the left.

Worked example 6 - g to kg

Convert 2500 g to kg.

2500g2.5kg÷ 1000
  1. Read it. Convert 2500 g to kg.
  2. The fact. 1000 g = 1 kg. g to kg: ÷ 1000.
  3. 2500 ÷ 1000 = 2.5.
  4. So 2500 g = 2.5 kg.
Answer: 2.5 kg
Watch outSame rule as m → km: divide by 1000.

Worked example 7 - l to ml

Convert 1.75 l to ml.

1.75l1750ml× 1000
  1. Read it. Convert 1.75 l to ml.
  2. The fact. 1 l = 1000 ml. l to ml: × 1000.
  3. 1.75 × 1000 = 1750.
  4. So 1.75 l = 1750 ml.
Answer: 1750 ml
Watch outSame rule as kg → g: multiply by 1000.

Worked example 8 - multi-step: mm to m

Convert 4500 mm to m.

4500mm4.5m÷ 1000
  1. Read it. Convert 4500 mm to m.
  2. The fact. mm to m in one go: ÷ 1000 (because 10 × 100 = 1000).
  3. 4500 ÷ 1000 = 4.5.
  4. Or step-by-step: 4500 ÷ 10 = 450 cm; 450 ÷ 100 = 4.5 m.
Answer: 4.5 m
Watch outTwo-step conversion. Either divide once by 1000 or divide twice (by 10, then 100).
Practice · Section A
Length: small units
mm ↔ cm · cm ↔ m
Practice · Section B
Bigger lengths & mass
m ↔ km · g ↔ kg
Practice · Section C
Capacity & multi-step
ml ↔ l · Multi-step conversions

Ready for more? 100 questions

When you have done these 12, you are ready for the bigger practice paper.

It has 100 questions. They start very easy and get harder near the end. Every question is still Grade 2 — nothing harder. You can stop at any time and come back.

Open the 100-question paper →

It opens in this same place. The lesson stays open behind it.

/ 12
Improve Tuition · George Street, Batley, West Yorkshire WF17 5AR · improvetuition.org
Teacher-led tuition since 2007.