Formulas
- Square: side². Rectangle and parallelogram: base × height.
- Triangle: base × height ÷ 2.
- Circle: π × radius². Circumference: 2 × π × radius.
- Trapezoid: (larger base + smaller base) × height ÷ 2.
- Rhombus: larger diagonal × smaller diagonal ÷ 2.
Example
A circle with a 5 ft radius has an area of about 78.54 ft² and a circumference of about 31.42 ft.
Frequently asked questions
Can I mix units?
No. Enter every measurement in the same unit; the area comes out in that unit squared.
See also
Results are estimates for information only and are not financial, legal or medical advice. Rates, taxes and fees vary — confirm with a professional or your lender.