---
title: "XIRR vs CAGR: When Each Applies to SIP Returns"
description: "Learn when CAGR fits a single investment and why XIRR uses dated cash flows for SIP returns, with a worked ACT/365 example and result checks."
author: "jordan-wells"
published: "2026-07-26T00:00:00.000Z"
tags: ["mutual-funds","sip","personal-finance"]
canonical: "https://smartmoney.report/blog/posts/xirr-vs-cagr-when-each-applies"
---

XIRR and CAGR answer different questions. CAGR describes the smooth annual growth of one beginning value to one ending value over a stated period. XIRR is designed for dated cash flows that need not be evenly spaced. A SIP has several contribution dates, so its return needs those dates and amounts; neither measure forecasts what will happen next.

## What is the difference between CAGR and XIRR?

CAGR, or compound annual growth rate, reduces a single beginning value and a single ending value to one annualised rate. If ₹1,00,000 becomes ₹1,44,000 exactly three years later, the calculation asks what constant annual rate would turn the first number into the second over that three-year period. Its standard form is `(ending value ÷ beginning value)^(1 ÷ years) − 1`.

For that illustration, the CAGR is about 12.92% a year. It is not the total gain of 44% simply divided by three: the formula asks for the annual compound rate that connects the two values. This is an arithmetic description of the stated endpoints, not a forecast of future returns.

That is useful when the record genuinely contains one starting value and one ending value. It does not record additions, withdrawals, dividends taken out, switches, or the dates on which they occurred.

XIRR, or extended internal rate of return, is for a schedule of dated cash flows that may be irregular. Spreadsheet documentation describes it as the internal rate of return for cash flows that are not necessarily periodic. The calculation uses each amount and its date, rather than pretending that every rupee entered on the same day.

The question is therefore not which label is more impressive. It is which calculation matches the record. A one-time purchase with one later value is an endpoint-growth question. A SIP, partial redemption, or series of additions is a dated-cash-flow question.

## When does CAGR fit the record?

CAGR fits a record with a single beginning value, a single ending value, and a clearly stated time period. It smooths the path between those endpoints. It does not say that returns arrived steadily each year, and it does not show volatility along the way. It is simply a way to express the compound growth implied by the two values and elapsed time.

For example, an investor who put ₹1,00,000 into one holding on a known date and later values the same holding at ₹1,44,000 after three full years has the inputs for a CAGR calculation. If there were no other cash flows, the beginning value, ending value, and period describe the record.

The answer changes if the investor made additional purchases along the way. Adding money in month two and month five means different amounts were invested for different lengths of time. An endpoint-only calculation cannot show that timing.

## When does XIRR fit a SIP or other cash-flow schedule?

XIRR fits a sequence of payments and proceeds with dates. From the investor's perspective, contributions are negative cash flows because money leaves the investor; a terminal portfolio value or redemption is positive because money returns. Both Microsoft and Google documentation require at least one negative and one positive cash flow to calculate the rate.

The date is part of the information, not decoration. Microsoft documents XIRR as using a 365-day year for discounting successive cash flows. The shared B01 calculation method states that ACT/365 convention visibly, so readers can see the date basis instead of assuming that every month has the same length.

Periodic IRR is related but narrower. Microsoft describes IRR as the internal rate for cash flows at regular intervals, such as monthly or annually. XIRR is the more appropriate label when the cash-flow dates themselves need to be supplied.

## Why cannot CAGR represent this six-payment example?

Consider an original B01 illustration. It records six ₹10,000 contributions on the first day of each month from January through June 2024, followed by a ₹66,000 terminal value on 1 January 2025. All signs below are from the investor's perspective.

| Date | Cash flow |
|---|---:|
| 2024-01-01 | -₹10,000 |
| 2024-02-01 | -₹10,000 |
| 2024-03-01 | -₹10,000 |
| 2024-04-01 | -₹10,000 |
| 2024-05-01 | -₹10,000 |
| 2024-06-01 | -₹10,000 |
| 2025-01-01 | +₹66,000 |

The total contributed is ₹60,000, but those six contributions were not invested for the same period. A CAGR based only on ₹60,000 and ₹66,000 would erase the contribution dates and answer a different hypothetical question. XIRR instead finds a rate that makes the dated present-value relationship balance to zero under the declared date convention.

Using `xirr-dated-cash-flow-act365-v1`, the shared B01 calculation returns 12.716895025021957%, displayed as **12.72%** after two-decimal rounding. Its XNPV residual is ₹0.0000033696851460263133. This is an arithmetic illustration, not a performance result, forecast, or recommendation.

## What do the signs and dates mean in practice?

Write every cash flow from one perspective and keep it consistent. For an investor measuring a portfolio, a purchase normally appears as a negative value and a sale, redemption, or terminal value as a positive value. Reversing the perspective reverses the signs, so a tool should label the convention rather than leave readers to infer it.

Dates should be real calendar dates, not vague labels such as “January” or “after a year”. A calculation also needs the same number of dates and amounts. A missing date, malformed number, or all-positive/all-negative schedule is not a small formatting problem; it means the requested rate is not defined by the stated inputs.

## What happens if XIRR cannot find a result?

XIRR is a root-finding calculation, not a button that can honestly return a percentage for every possible schedule. Microsoft documents an iterative method and a `#NUM!` result when it cannot find a working answer within its limit. The B01 calculator gives a plain-language failure state rather than substitute a rate.

It also identifies non-conventional cash-flow patterns. A schedule that changes sign more than once can have more than one mathematical solution. Selecting one invisible answer could be misleading, so the original calculation contract flags that pattern as ambiguous instead of making a personal-finance claim from it.

## Does a calculated annual return predict a future return?

No. CAGR and XIRR describe the cash-flow record and assumptions supplied to the calculation. They do not forecast a fund, security, index, or portfolio. A high or low historical result can reflect when money was added or withdrawn as well as what happened to the underlying value.

For a broader introduction to the mechanics of regular investing, see the [mutual-funds hub](/mutual-funds). For a discussion of the distinction between a one-time investment and recurring contributions, see [SIP versus lumpsum in index funds](/blog/posts/sip-vs-lumpsum-in-index-funds-what-does-the-data-say). These are background links, not individual guidance.

## What should a return calculation disclose?

A result is easier to interpret when its inputs are inspectable. At a minimum, record the cash-flow amounts, dates, sign convention, date-count check, day-count convention, calculation version, and display-rounding rule. A person reviewing a result should also know whether the schedule represents contributions only, a partial redemption, a dividend, fees, or a terminal portfolio value.

That transparency does not make the number a recommendation. It makes the measurement question auditable: which cash entered or left, on which dates, and what convention converted that history into an annualised rate?

## Sources

1. [Microsoft Support: XIRR function](https://support.microsoft.com/en-us/excel/functions/xirr-function) (Microsoft) - checked 2026-07-26
1. [Microsoft Support: IRR function](https://support.microsoft.com/en-us/excel/functions/irr-function) (Microsoft) - checked 2026-07-26
1. [Google Docs Editors Help: XIRR](https://support.google.com/docs/answer/3093266?hl=en) (Google) - checked 2026-07-26