The perimeter of a regular pentagon is the total length of its outline — the sum of all five equal sides. You calculate it to fence a pentagonal plot, frame a five-sided shape, or measure how much material you need to go all the way around.

The Formula

P = 5 × t

• P — perimeter of the pentagon (cm, m, etc.)
• t — side length (all five sides are equal)

Because all five sides are equal, the perimeter is simply the side length multiplied by five. No approximations needed — it is an exact calculation.

Step-by-Step Example