What Is the Parallelogram Perimeter Calculator?
A parallelogram is a four-sided figure (quadrilateral) where opposite sides are parallel and equal in length. Because the two pairs of opposite sides are equal, you only need two adjacent side measurements — labelled a and b — to find the full distance around the shape. This calculator computes that perimeter instantly.
How to Use It
Enter the length of side a and the length of the adjacent side b in any consistent unit (cm, m, inches, etc.). The calculator returns the perimeter in that same unit. As long as both sides use the same measurement unit, the answer will be correct.
The Formula Explained
The perimeter of a parallelogram is given by:
$$P = 2 \times (a + b)$$
Since a parallelogram has two sides of length \(a\) and two sides of length \(b\), adding all four gives \(a + a + b + b = 2a + 2b\), which factors neatly into \(2 \times (a + b)\).
Worked Example
Suppose a parallelogram has side \(a = 5\) cm and side \(b = 8\) cm. Then:
$$P = 2 \times (5 + 8) = 2 \times 13 = 26 \text{ cm}.$$
FAQ
Do I need the angles or the height? No. The perimeter depends only on the side lengths, not on the angles or the slant height. Height is only needed for area.
What units does it use? Any unit you like — just keep both sides in the same unit and the perimeter comes out in that unit.
Is a rectangle a parallelogram? Yes. A rectangle is a special parallelogram, and the same formula \(P = 2 \times (a + b)\) gives its perimeter.
