## The Core Difference

**IRR (Internal Rate of Return)** assumes cash flows happen at _regular intervals_ (monthly, yearly, etc.).

**XIRR (Extended IRR)** uses _exact dates_ for each cash flow, making it accurate for real-world investments.

### 📊 IRR  
**Internal Rate of Return**  
- • Cash flows must be equally spaced  
- • Uses period numbers (1, 2, 3...)  
- • Common in corporate finance  
- • Excel: `=IRR(values)`

### 📈 XIRR  
**Extended Internal Rate of Return**  
- • Cash flows can be on any date  
- • Uses exact dates  
- • Perfect for investments  
- • Excel: `=XIRR(values, dates)`

## Example 1: When IRR Works  
Suppose you invest ₹10,000 at the start of each year for 3 years:

| Period | Cash Flow |
| --- | --- |
| Year 0 | -₹10,000 |
| Year 1 | -₹10,000 |
| Year 2 | -₹10,000 |
| Year 3 | +₹40,000 |

IRR = **15.74%** annually  
IRR works here because investments are exactly 1 year apart.

## Example 2: When You Need XIRR  
Now let's say your investments happened on actual dates:

| Date | Cash Flow |
| --- | --- |
| 15-Jan-2021 | -₹10,000 |
| 20-Mar-2021 | -₹10,000 |
| 05-Sep-2022 | -₹10,000 |
| 30-Dec-2023 | +₹40,000 |

XIRR = **17.82%** annually

The XIRR is higher because ₹10,000 invested in Sep 2022 had less time to grow (only ~15 months vs 3 years for the first investment).

#### ⚠️ If you used IRR here...  
IRR would assume equal yearly spacing and give you **15.74%** — understating your true return by over 2%!

### 🎯 Rule of Thumb  
If your cash flows happen on **specific dates** (which is almost always true for personal investments), use **XIRR**. Only use IRR when cash flows are perfectly periodic.

## Summary  
- **IRR** = For equally-spaced cash flows (monthly, yearly)  
- **XIRR** = For real-world investments with specific dates  
- XIRR is more accurate for SIPs, trading, and any irregular investments  
- When in doubt, use XIRR—it works for all cases

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