XIRR means Extended Internal Rate of Return. In a mutual fund account, it measures an annualised return while taking account of the amount and date of each investment or withdrawal. It is useful when money enters at different times, as happens with SIP instalments. CAGR answers a simpler question: what constant annual growth rate connects one starting investment to one ending value?

MeasureWhat it captures
XIRRAmounts and exact dates of multiple cash flows
CAGRGrowth between a starting amount and ending value
Absolute returnPercentage change without annualising

The distinction is explained in Tata Mutual Fund's investor education article and HSBC Mutual Fund's comparison. Neither number is a promised return. Both describe a particular set of past values and dates.

How is XIRR calculated?

Start with a transaction ledger. Record contributions as negative numbers because they leave the investor's pocket. Record withdrawals as positive numbers. On the valuation date, add the remaining portfolio value as a final positive cash flow. This last entry lets the calculation include units that are still held; it does not mean those units have actually been sold.

The equation is: sum of [C_i / (1 + r)^((d_i - d_0)/365)] = 0. Here C_i is each signed cash flow, d_i is its date, d_0 is the first date and r is the annual rate being solved for. The spreadsheet function is =XIRR(values, dates). Values and dates must cover matching rows. Software searches for a rate that makes the equation balance.

Consider this independently calculated illustration, which uses invented transactions rather than any scheme's performance. An investor contributes Rs 10,000 on 1 January 2021 and another Rs 10,000 on 1 January 2022. On 1 January 2023 the holding is worth Rs 23,100. There are exactly 365 days between each pair of adjacent dates in this example.

DateCash flow
1 January 2021Minus Rs 10,000
1 January 2022Minus Rs 10,000
1 January 2023Plus Rs 23,100

The XIRR is 10%. At that rate, the first Rs 10,000 grows for two years to Rs 12,100 and the second grows for one year to Rs 11,000. Together they equal Rs 23,100. The check is 10,000 x 1.10^2 + 10,000 x 1.10 = 23,100. These assumptions make the arithmetic transparent; they do not forecast a future SIP result.

Why does CAGR give a different answer for a SIP?

CAGR = (ending value / starting value)^(1 / years) - 1. For a single Rs 10,000 contribution that becomes Rs 12,100 after two years, CAGR is 10%. That fits because all the money was present from the beginning. The same shortcut cannot faithfully describe instalments that arrived later.

If someone incorrectly treats the Rs 20,000 contributed in the earlier example as though it was all invested on day one, the result is (23,100 / 20,000)^(1/2) - 1, or about 7.47%. That lower number is a consequence of the wrong starting assumption. It is not evidence of an extra charge or missing money.

Nor does dividing the Rs 3,100 gain by Rs 20,000 solve the timing problem. That gives 15.5%, a simple gain relative to total contributions, without assigning a holding period to each contribution. It is useful for understanding rupee profit, but it is not an annual rate for this transaction pattern.

What should you check when an app shows XIRR?

Check the valuation date first. Next, check that every contribution and withdrawal appears once, with the correct sign. A partial withdrawal belongs in the ledger as money received. Leaving it out makes the account appear to have less value than it actually delivered. Entering the current holding twice creates the opposite error.

Compare the same scope. A single scheme's XIRR and an entire portfolio's XIRR may cover different transactions. Two people holding the same scheme can have different personal returns because they invested on different dates. A factsheet's historical CAGR and an investor's personal XIRR therefore need not match.

Axis Mutual Fund's explanation separates absolute return, CAGR and XIRR and discusses the limits of relying on past performance. An annualised percentage does not show the size of interim falls, the amount invested, or whether a gain has been realised. Keep the transaction ledger beside the percentage.

For the surrounding calculations, read our guides to the SIP calculator formula, mutual fund NAV and SWP withdrawals and units. They explain different parts of the account; none turns a historical return into a guarantee.