# Excel PI Function

The Excel PI function returns the value of the geometric constant π (pi). The value represents a half-rotation in the radian angle system. The constant appears in many formulas relating the the circle such as the area of a circle.

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.

=PI() // Returns 3.14159265358979

### Example #1

The constant π appears in many math formulas relating to the circle. The formula for 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

### Example #2

The area enclosed by a circle with radius (r) is defined by the following formula: πr^{2}. With radius in cell A1, the same formula in Excel with the PI() function is:

=PI()*A1^2

### Example #3

To convert an angle measured in radians in terms of π, the DEGREES function can be used to get the corresponding angle in degrees:

See wumbo.net for a more detailed explanations of key math concepts and formulas.

## Download 100+ Important Excel Functions

Get over 100 Excel Functions you should know in one handy PDF.