What Is the Perimeter of a Quadrilateral?
A quadrilateral is any four-sided polygon — squares, rectangles, trapezoids, parallelograms, kites, and irregular four-sided shapes all qualify. Its perimeter is simply the total distance around the outside, which you find by adding the lengths of all four sides. This calculator works for any quadrilateral as long as you know the four side lengths, regardless of the angles between them.
How to Use This Calculator
Enter the four side lengths — labeled a, b, c, and d — using any single unit of measurement (centimeters, meters, inches, feet). Make sure every side uses the same unit. The calculator instantly returns the perimeter in that same unit. Because the perimeter only depends on the side lengths, you do not need to know the shape's angles or area.
The Formula Explained
The perimeter formula is $$P = a + b + c + d$$, where \(a\), \(b\), \(c\), and \(d\) are the four sides. For a square (all sides equal) this simplifies to \(P = 4s\), and for a rectangle (opposite sides equal) it becomes \(P = 2(\text{length} + \text{width})\). This general form handles every case, including completely irregular quadrilaterals.
Worked Example
Suppose a garden plot has sides measuring 5 m, 6 m, 7 m, and 8 m. The perimeter is $$P = 5 + 6 + 7 + 8 = 26 \text{ meters}$$ If you wanted to fence it, you would need 26 meters of fencing material.
FAQ
Does the shape's angle matter? No. The perimeter depends only on the side lengths, not the interior angles.
Can I use this for a square or rectangle? Yes. Just enter the repeated side lengths — for a 4×4 square, enter 4 for all four sides.
What units does it return? The result is in the same unit you used for the inputs. The tool does no unit conversion, so keep all four sides in one unit.
