Perimeter Practice
Practise finding perimeter — the total distance all the way around a shape.
Practice now
How to find perimeter
Perimeter is simply the distance around the outside of a shape — add up the lengths of all its sides. The formulas are just shortcuts for that adding.
- Any shape: add up every side.
- Rectangle: 2 × (length + width) — two of each side.
- Square or regular polygon: number of sides × side length.
Worked examples
Tips & common mistakes
Perimeter is a length, so the answer is in plain units, not square units — that’s how you tell it apart from area. For regular shapes, multiplying by the number of sides is faster than adding them one by one. Type the number.
- Multiplying length by width — that’s area, not perimeter.
- For a rectangle, adding length and width only once instead of doubling.
- Missing a side when adding around an irregular shape.
Frequently asked questions
How do you find perimeter?
Add the lengths of all the sides. For a rectangle that’s 2 × (length + width); for a regular shape it’s sides × side length.
What’s the difference between area and perimeter?
Perimeter is the distance around the edge (units); area is the space inside (square units).
How do you find the perimeter of a square?
Multiply one side by 4, since all four sides are equal.
What about a regular pentagon or hexagon?
Multiply the side length by the number of sides — 5 for a pentagon, 6 for a hexagon.
What grade is perimeter?
Perimeter is introduced in grade 3 and practised through grade 5.