Method
Rectangle area = width × height. Triangle area = base × height ÷ 2. Circle area = πr².
Example
A rectangle 8 m by 5 m has area 40 m² and perimeter 26 m.
Limits
Check inputs and units. Important academic, financial or professional decisions should be confirmed against an appropriate source.
Common questions
What does the area and perimeter calculator calculate?
Calculate area and perimeter for rectangles, triangles and circles.
Does this area and perimeter calculator show its method?
Yes. The result includes the central formula or working needed to check the answer.
Are my values uploaded?
No. The calculation runs in this browser and does not require an account.