How to use pi in Excel
Formula (Excel and Google Sheets)
=PI()*B2^2Use the PI function, =PI(), which returns 3.14159265358979; a circle's area is =PI()*B2^2.
- Result on the example
- one result per row in
C2, filled down toC6 - Works in
- Every current version
- Google Sheets
- Same formula
See it work
The formula is already in C2, filled down to C6. Change any input and the result updates, or edit the formula to experiment.
How it works
PI takes no arguments but still needs its empty parentheses. It returns π to 15 digits. The power comes before the multiplication, so PI()*B2^2 squares the radius and then multiplies by π.
=PI()*B2^2Result0.7853981634
PI()3.141592654PI: The constant π.B20.5The value in B2.
B2^20.25The ^ operator raises to a power.
PI()*B2^20.7853981634The * operator multiplies.
In Google Sheets
The same formula works in Google Sheets: =PI()*B2^2. We ran it in Google Sheets mode on the same data and it returns the same results.
Other ways to do it
Each one was run on the same example sheet.
| Formula | Result | When to use it |
|---|---|---|
| =PI()*POWER(B2,2) | 0.785, 1.767, 3.142… | POWER spells out the square. |
| =PI()*B2*B2 | 0.785, 1.767, 3.142… | Multiplying the radius by itself avoids the order-of-operations question. |
Common mistakes
- Typing
=PI*B2^2without the parentheses returns #NAME?. - Typing 3.14 instead of PI() is off from the third digit; results drift on large values.
Try it yourself
Same data, empty answer cell. Your formula is graded instantly, then re-checked on changed data, so a typed-in number won't pass.
Use pi
C2, calculate the area of a circle with the radius in B2 (π × r²), then fill down to C6.Questions
How do I calculate a circumference?
Use =2*PI()*B2.
How do I convert degrees to radians?
Multiply by PI()/180: =B2*PI()/180, or use =RADIANS(B2).
Checked by running on 2026-10-30: every formula and result on this page was calculated by the Spreadsheet Practice formula engine, in both Excel and Google Sheets modes.