Measure Area with Unit Squares
Lesson preview: the Mini Lesson and Vocabulary are open to everyone. Guided practice, exercises, the parent checklist and the printable PDF worksheet come with full access (free 7-day trial or membership).
What you will learn
- 1Count unit squares to find the area of a shape in both square inches (in²) and square centimeters (cm²)
- 2Compare areas of different shapes on a grid using square inches and square centimeters
Mini Lesson
Area is the amount of surface a shape covers. We measure area in square units. To find the area of a shape on a grid, count how many unit squares fit inside it. Each unit square can be 1 in × 1 in (one square inch, in²) or 1 cm × 1 cm (one square centimeter, cm²). The math is the same in both unit systems — just keep your units consistent.
Counting Unit Squares
- Draw or look at the shape on a grid of inch or centimeter squares.
- Count each complete unit square inside the shape.
- The total count is the area — write it in in² (square inches) or cm² (square centimeters).
- For rectangles: area = rows × columns, or length × width (multiply instead of counting).
A rectangle is 4 units wide and 3 units tall on a centimeter grid. What is its area?
Comparing Areas
- Two shapes can have the same perimeter but different areas.
- To compare, count the unit squares in each shape — but only compare shapes drawn on the same kind of grid (in² with in², cm² with cm²).
- The shape with more unit squares has a larger area.
Words to know
Area
The amount of space inside a flat shape
e.g. A rectangle has an area of 12 in² or 12 cm² depending on the grid.
Unit square
A square that is 1 unit on each side (1 in × 1 in or 1 cm × 1 cm)
e.g. I count unit squares to find the area.
Square inch
A US customary unit of area — a square that is 1 in × 1 in (written in²)
e.g. The area of this card is 12 in².
Square centimeter
A metric unit of area — a square that is 1 cm × 1 cm (written cm²)
e.g. The area of this sticker is 12 cm².
Length
How long one side of a shape is, in inches or centimeters
e.g. The length is 6 in or 6 cm.
Width
How wide a shape is, in inches or centimeters
e.g. The width is 4 in or 4 cm.
For rectangles on a grid, multiply rows × columns. Always write the unit: in² (square inches) or cm² (square centimeters).
Unlock the full HSEA system for 7 days.
Add your first kid profile and your 7 days start: every lesson in every grade, saved progress for each child. Nothing to set up, no card required, nothing to cancel.
- ✓ All 1,880 lessons, Grades 1–6, every subject
- ✓ Profiles + saved progress for every kid
- ✓ Printable lessons with answer key