Real investments rarely grow by the same amount two years running. They jump, fall and jump again. Compound Annual Growth Rate strips out that year-to-year noise and answers one question: what single steady annual rate would have taken this investment from its starting value to its ending value over this period?
It is a smoothed, backward-looking number. Nothing actually grew at that rate. It is the rate that would have produced the same destination.
The formula, in words
Divide the ending value by the beginning value, raise the result to the power of one divided by the number of years, then subtract one.
If Rs 1,00,000 grows to Rs 2,00,000 over 6 years, the ratio is 2. The sixth root of 2 is about 1.122, so the CAGR is roughly 12.2%.
A worked example that shows why it is needed
Suppose a fund's actual annual returns over five years are:
- Year 1: plus 30%
- Year 2: minus 15%
- Year 3: plus 25%
- Year 4: minus 5%
- Year 5: plus 20%
The simple average of those five numbers is 11%. But an investment of Rs 1,00,000 actually ends at about Rs 1,59,800, which is a CAGR of about 9.8%.
The simple average overstates the outcome, and it always will when returns fluctuate, because a loss requires a larger percentage gain to recover from. A 50% fall needs a 100% rise to get back to level. CAGR accounts for this automatically. A simple average never does.
Where CAGR is the right tool and where it is not
CAGR assumes one amount invested at the start and left untouched until the end. That makes it correct for:
- A lumpsum mutual fund investment
- A fixed deposit or PPF balance over a defined period
- A property bought once and sold once
- Comparing two funds over the same fixed window
It is the wrong tool the moment money goes in or out at different dates. A monthly SIP makes 36 separate investments over three years, each held for a different length of time. Applying CAGR to the total invested against the final value overstates or understates the return depending on the pattern. That is what XIRR exists for, and it is the number Indian mutual fund statements now report for SIPs.
What CAGR deliberately hides
| Fund A | Fund B | |
|---|---|---|
| 3 year CAGR | 12% | 12% |
| Worst single year | minus 4% | minus 38% |
| Best single year | plus 21% | plus 61% |
| Path | Steady | Violent |
Both funds have the same CAGR and are not remotely the same investment. Fund B is far harder to hold, and an investor who panicked and sold at the bottom would never have realised that 12%.
CAGR tells you where you arrived. It says nothing about how uncomfortable the journey was, and discomfort is what causes people to sell at the wrong time.
Two more limitations worth knowing
Start and end dates are chosen, and can be chosen flatteringly. A 5 year CAGR measured from a market bottom looks spectacular. The same fund measured from the peak a year earlier looks poor. When you see an impressive CAGR in marketing material, check the window, and compare rolling returns across several starting points rather than one convenient one.
It is not adjusted for inflation or tax. A 9% CAGR while inflation runs at 6% is a real return of roughly 3%, before any tax on capital gains. The headline number flatters.
Typical benchmarks in India
Useful reference points, though none is a promise: bank fixed deposits have run around 6% to 7.5%, PPF around 7% to 8%, EPF slightly above that, and broad Indian equity indices have delivered low-to-mid teens over multi-decade periods with severe interim drawdowns. Any product advertising a guaranteed CAGR far above these ranges deserves suspicion rather than interest.
Work out the CAGR on your own investments with our CAGR calculator.