Perimeter of a parallelogram is the total length of its sides and it is calculated by adding together the length of all its sides (as it is calculated for any other polygon).

**P = a + a + b + b**

Where *P* is perimeter of the parallelogram, *a* is the longer side, and *b* is the shorter side.

Example:

If *a = 8 units* and *b = 5 units* then the perimeter of the parallelogram is:

P = a + a + b + b = 8 + 8 + 5 + 5 = 26 units