1. What is XIRR (Extended Internal Rate of Return)?
XIRR is a highly precise financial calculation used to determine the annualized return of an investment portfolio with multiple transactions occurring at irregular intervals. Unlike simple CAGR, which assumes a lump sum deposit made on day one and withdrawn entirely at the end, XIRR handles regular SIP flows, occasional dynamic lump sums, dividends, and irregular withdrawals easily.
CHECK OUT OUR ROI CALCULATOR2. How Does XIRR Differ from CAGR and IRR?
Choosing the correct return metrics is vital to auditing investment health:
- CAGR (Compound Annual Growth Rate): Calculated using only two points in time—the beginning value and the final ending value. It ignores any intermittent transactions or timing.
- IRR (Internal Rate of Return): Handles multiple deposits and cash flows, but assumes they occur at regular, equal periodic steps (e.g., exactly once a year or exactly on the first of each month).
- XIRR (Extended IRR): Accommodates irregular schedules down to the exact calendar date. It uses the Newton-Raphson numerical algorithm to solve the internal rate of return equations.
3. The Mathematics and Equation Behind XIRR
XIRR acts by finding the specific discount rate r that sets the Net Present Value (NPV) of all Cash Flows (both positive and negative) equal to exactly zero. The formula solved iteratively is:
0 = Σ [ C_i / (1 + r)^((d_i - d_1) / Y) ]- Where C_i represents the net cash flow value of transaction i.
- d_i is the calendar date of the transaction.
- d_1 represents the baseline start date of the first transaction.
- Y is the Year Basis (commonly 365, 366, or actual year lengths).