Greek Small Letter Pi

Symbol Format Data
π Code Point
pi SVG
Symbol Table


The Greek small letter (pi) is used in trigonometry as a constant to represent a half-rotation around a circle in radians. The value of is approximately and appears in many math formulas and expressions. Read more…


capital pi

The capital Greek letter Π (Pi) is used in algebra to represent the product operator. The product operator has three parts: the initial index value, an end value, and the expression being multiplied together.



The greek letter π (pi) is a geometric constant approximately equal to 3.1416. Its value is equal to the length of any circle's circumference divided by its diameter.

Circumference of Circle π (pi)

The circumference of a circle is given the constant π (pi) multiplied by two times the radius of the circle.

Area of Circle π (pi)

The traditional formula for the area of a circle is given in terms of the geometric constant π (pi).

Radian Angle System

Radians are a unit that measures angle using the radius of a circle. One radian is equal to the amount of rotation required to travel the length of one radius along the circumference of the circle.