math.pi
The number π, the ratio of a circle’s circumference to its diameter.
Python 3.13
math.piReturn value
The float 3.141592653589793.
Examples
The value of π
Python 3.13
import math
print(math.pi)3.141592653589793
Area of a circle
Python 3.13
import math
radius = 2
print(round(math.pi * radius ** 2, 2))12.57
Details
It is a constant, not a function: write it without parentheses, math.pi() raises TypeError. The value is approximate, so math.sin(math.pi) gives a very small number instead of 0. For a full turn, there is the math.tau constant equal to 2π.