How to calculate a cube root in Excel
Formula (Excel and Google Sheets)
=B2^(1/3)Raise the number to the power of one third, =B2^(1/3), and use 1/n for any nth root.
- 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
Excel has no CBRT function, but a cube root is the power 1/3: 3 × 3 × 3 = 27, so 27^(1/3) is 3. The parentheses matter, because ^ is calculated before division.
=B2^(1/3)Result3
B227The value in B2.
1/30.3333333333The / operator divides.
B2^(1/33The ^ operator raises to a power.
In Google Sheets
The same formula works in Google Sheets: =B2^(1/3). 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 |
|---|---|---|
| =POWER(B2,1/3) | 3.00, 4.00, 4.64… | POWER is the function form of the same calculation. |
Common mistakes
=B2^1/3without parentheses means (B2^1)/3: 27 becomes 9.- A negative number to a fractional power returns #NUM! in Excel, even though -8 has the cube root -2. Use
=SIGN(B2)*ABS(B2)^(1/3).
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.
Calculate a cube root
C2, calculate the edge length of a cube-shaped tank with the volume in B2, then fill down to C6.Questions
How do I calculate any nth root?
Use =B2^(1/n), for example =B2^(1/4) for a fourth root.
Why does the result show 3.9999999999?
Powers are calculated in binary, so roots can be off in the 15th digit. Wrap in ROUND if you compare results: =ROUND(B2^(1/3),10).
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.