Use the formula: `=(Ending Value/Beginning Value)^(1/Number of Years)-1`
Replace `Ending Value` with the final value cell reference
Replace `Beginning Value` with the initial value cell reference
Replace `Number of Years` with the number of years cell reference or a number
Format the result cell as Percentage
Example formula: `=(B2/A2)^(1/C2)-1`
If the period is in months, convert months to years first
If the period is in days, convert days to years first
Use absolute references if copying the formula across cells
Handle zero or negative values before applying the formula