Perimeter Calculator
Calculate the perimeter and area of a rectangle, circle or triangle. Pick a shape, enter the dimensions, and choose your unit — great for fencing, rooms, plots and fields.
Perimeter
—
— area
Perimeter Formulas
| Shape | Perimeter | Area |
|---|---|---|
| Rectangle | 2 × (length + width) | length × width |
| Circle | 2 × π × radius | π × radius² |
| Triangle | side A + side B + side C | Heron’s formula |
For triangles, the area uses Heron’s formula: with s = perimeter ÷ 2, area = √(s(s−a)(s−b)(s−c)). The three sides must each be shorter than the other two combined, or they can’t form a triangle.
Measure Irregular Shapes on a Map
Real plots and fields are rarely perfect rectangles. To measure an irregular boundary, trace it point-by-point with the land surveying tool — Distance Map sums the perimeter and calculates the enclosed area automatically, in meters, feet, acres or hectares.
Get Distance Tool
Download Distance Tool for iOS and start measuring in seconds.
