Measurements for Class 3: Length, Weight and Capacity

Measurements for Class 3 is an essential maths topic that helps children understand how we measure objects and quantities in everyday life. This lesson on Measurements for Class 3 teaches length, weight and capacity using simple, hands-on examples so students learn to estimate, compare and record measurements confidently. Children will practise using units like centimetres, metres, grams, kilograms, millilitres and litres, and learn to add and compare measurements in real-life situations. This approach builds practical skills for classroom problems and daily tasks. In this guide you will learn how to measure length, weight and capacity, estimate and check answers, and use standard units confidently.

Table of Contents

• Measuring Length
• Measuring Weight
• Measuring Capacity
• Number Stories

Measuring Length

Length tells us how long, tall, or far something is. We use the metric system for measuring length. The standard unit of length is the metre (m). But we also use smaller and larger units depending on what we are measuring.

Units of Length

 

 

Note: 

• 1 cm = 10 mm  

• 1 m = 100 cm 

• 1 km = 1,000 m 

• 1 m = 1,000 mm

Reading Length on a Ruler

 

When you place a pencil on a centimetre ruler, you read its length by looking at where the tip lands. 

Here, the pencil's tip falls between 6 cm and 7 cm on the scale, reaching 5 smaller markings after the 6 cm mark. Each smaller marking = 1 mm. So the pencil is 6 cm 5 mm long.

Comparing Lengths

To compare two lengths, always start with the bigger unit first. If both bigger units are the same, then compare the smaller units.

Example 1:  Compare 11 m 32 cm and 18 m 56 cm

Compare metres: 11 < 18

∴ 11 m 32 cm < 18 m 56 cm

Example 2: Compare 4 km 105 m and 4 km 92 m

Kilometres are equal (both 4 km)

Compare metres: 105 > 92

∴ 4 km 105 m > 4 km 92 m

Converting Units of Length

Rule: Bigger → Smaller unit: Multiply

Smaller → Bigger unit: Divide

Adding and Subtracting Lengths

Follow these three steps every time:

• Arrange numbers in columns by unit (bigger unit in one column, smaller unit in another)

• Add or subtract the smaller unit column first

• Add or subtract the bigger unit column

 

Example 1: Add 2 km 348 m and 3 km 126 m

kmm2348+31265474

2 km 348 m + 3 km 126 m = 5 km 474 m

Example 2: Subtract 28 m 39 cm from 87 m 69 cm

mcm8769−28395930

87 m 69 cm - 28 m 39 cm  = 59 m 30 cm

Measuring Weight

Weight tells us how heavy an object is. We measure weight using a weighing balance.

Units of Weight

Note: 

• 1 g = 1,000 mg 

• 1 kg = 1,000 g

Comparing Weights

Just like length, we compare the weight of the objects.

Example 1: Compare 3 kg 432 g and 7 kg 26 g

Compare kg: 3 < 7

∴ 3 kg 432 g < 7 kg 26 g

Example 2: Compare 2 g 500 mg and 2 g 85 mg

Grams are equal (both 2 g). Compare mg: 500 > 85

∴ 2 g 500 mg > 2 g 85 mg

Converting Units of Weight

Adding and Subtracting Weights

Arrange by units, add/subtract the smaller unit first, then the bigger unit.

Example 1: Add 3 kg 283 g and 4 kg 512 g

kgg3283+45127795

3 kg 283 g + 4 kg 512 g = 7 kg 795 g

Example 2: Subtract 6 g 364 mg from 8 g 876 mg

gmg8876−63642512

8 g 876 mg - 6 g 364 mg = 2 g 512 mg

Measuring Capacity

Capacity is the amount of liquid a container can hold. The standard unit for measuring capacity is the litre (l). For smaller amounts, we use millilitre (ml).

 

Note: 1 l = 1,000 ml

Comparing Capacities

Example 1: Compare 1 l 205 ml and 854 ml

1 l = 1,000 ml, which is already more than 854 ml

∴ 1 l 205 ml > 854 ml

Example 2: Compare 7 l 90 ml and 7 l 900 ml

The litres are equal (both 7 l). Compare ml: 90 < 900

∴ 7 l 90 ml < 7 l 900 ml

Converting Units of Capacity

Adding and Subtracting Capacity

Example 1: Add 5 l 535 ml and 4 l 348 ml

lml5535+43489883

5 l 535 ml + 4 l 348 ml = 9 l 883 ml

Example 2: Subtract 1 l 383 ml from 5 l 497 ml

lml5497−13834114

5 l 497 ml - 1 l 383 ml = 4 l 114 ml

Number Stories

1. Ritika bought 1 kg 250 g of sugar and 2 kg 200 g of jaggery. What is the total weight?

Solution: Amount of sugar =  1 kg 250 g 

Amount of jaggery = 2 kg 200 g

Total weight = 1 kg 250 g + 2 kg 200 g = 3 kg 450 g

2. Raghav's notebook is 18 cm 2 mm long and Sarika's is 20 cm 5 mm long. Whose is longer and by how much?

Solution: Length of Raghav's notebook = 18 cm 2 mm

 Length of Sarika's notebook = 20 cm 5 mm

Difference in length =  20 cm 5 mm − 18 cm 2 mm = 2 cm 3 mm

Sarika's notebook is longer by 2 cm 3 mm

3. Aditi has a ribbon of 4 m 78 cm. She used 2 m 27 cm for a project. How much is left?

Solution: Total length of ribbon = 4 m 78 cm

Length of ribbon used = 2 m 27 cm

Remaining length of ribbon = 4 m 78 cm − 2 m 27 cm = 2 m 51 cm

 

Here's a set of questions for practice. Solve them in a notebook with a proper layout.

Worksheet on Measurements for Class 3