Purpose
Return value
Syntax
=PI()How to use
The PI function returns the value of π (pi) accurate to 15 digits. The value of π represents a half-turn in radians and appears in many formulas relating to the circle. The PI function takes no arguments:
=PI() // returns 3.14159265358979
Circumference of a circle
The constant π appears in many math formulas relating to the circle. The formula for the circumference of a circle is 2πr. Given a radius of 3, the same formula in Excel is:
=2*PI()*3 // circumference of circle, r=3
Area of a circle
The area enclosed by a circle with radius (r) is defined by the following formula: πr2. With radius in cell A1, the same formula in Excel with the PI() function is:
=PI()*A1^2
Radians to degrees
To convert an angle measured in radians in terms of π, the DEGREES function can be used to get the corresponding angle in degrees:
=DEGREES(PI()) // Returns 180°
=DEGREES(2*PI()) // Returns 360°
See wumbo.net for a more detailed explanation of key math concepts and formulas.
PI function examples
Volume of a sphere
Surface area of a cone
Surface area of a sphere
Volume of a cone
Area of a circle
Circumference of a circle
Surface area of a cylinder
Volume of a cylinder
Related functions
RADIANS Function
The Excel RADIANS function converts degrees to radians. For example, =RADIANS(180) returns 3.1415 or the value of π (pi)....
DEGREES Function
The Excel DEGREES function converts angles (expressed in radians) to degrees. For example, the formula =DEGREES(PI()) returns 180.
