Why annualised return is a fairer comparison than total return
Total return tells you how much an investment has grown in absolute percentage terms over its entire holding period, but it doesn't account for how long that growth took to achieve — a 50% total return over three years is a very different result from the same 50% total return over fifteen years. The Compound Annual Growth Rate (CAGR), which this calculator produces, expresses that same growth as a single smoothed annual percentage, which is the only way to sensibly compare investments held for different lengths of time or against a benchmark like a savings rate or an index fund's published average return.
What CAGR does and doesn't tell you
CAGR smooths out the actual year-to-year path an investment took to get from its starting value to its current value, which is useful for comparison but hides the real journey. Two investments could have an identical CAGR over five years while one rose steadily and the other fell sharply before recovering strongly — CAGR alone can't distinguish between those very different (and very differently risky) experiences. It's a useful headline figure, but it isn't a complete picture of volatility or risk.
Why this calculator assumes no additional contributions
This tool compares a single starting value to a single ending value, which works cleanly if you invested a lump sum once and left it untouched. If you made regular additional contributions along the way — as many investors saving into a pension or ISA do — a simple CAGR calculation on the total pot will overstate or understate your actual personal rate of return, because it can't distinguish growth on your original capital from the effect of adding new money partway through. For that scenario, our investment growth calculator and regular investment calculator are more appropriate, since they model contributions directly.
Comparing your return against a benchmark
Once you have your own annualised return, it's worth comparing it against a relevant benchmark — a comparable index fund's published long-term average, a cash savings rate over the same period, or inflation over that period specifically — rather than judging the number in isolation. A 6% annualised return might look respectable on its own, but tells a very different story depending on whether inflation over that same period ran at 2% or 8%. Our inflation calculator can help translate a nominal return like this into real, inflation-adjusted terms.
Using this to check platform or fund performance reporting
Investment platforms and fund factsheets often quote annualised returns over standard periods (one, three, five and ten years), and this calculator lets you reproduce that same style of figure for your own specific holding period and dates, rather than relying only on the standard periods a provider chooses to publish. This is a useful independent check when you're deciding whether to keep, top up or move an existing investment.
A worked example
Say you invested £10,000 six years ago and it's now worth £16,500, matching the calculator's defaults. The total gain is £6,500, a total return of 65% over the whole period. Run through the CAGR formula, though, and the annualised figure comes out at roughly 8.7% a year — a meaningfully more modest-sounding number than "65%", even though both describe exactly the same underlying result, just expressed over different timeframes.
Now compare that against a second investment: £10,000 that grew to £13,500 over just two years. Its total return of 35% looks smaller than the first example's 65%, but its CAGR works out at around 16.2% a year — almost double the annualised rate of the first investment. This is exactly why annualised return, not total return, is the fairer way to compare two investments held for different lengths of time.
Watch out for survivorship and selection bias
It's tempting to calculate a glowing annualised return on a single successful holding and conclude that a particular approach or fund works well, but a single result tells you very little on its own — especially if you only remember to calculate it for the investments that did well, while forgetting or ignoring the ones that didn't. A fair assessment of any investment strategy looks at the whole portfolio's blended return over a meaningful period, not the standout performer picked out afterwards, since focusing only on winners can create a badly distorted impression of how well a strategy has actually performed overall.
Frequently asked questions
What's a reasonable annualised return to expect from investing?
Long-run historical averages vary considerably by asset mix, region and the specific period studied, and past performance is never a guarantee of future results — this is precisely why a regulated adviser or the fund's own published long-term data is a better guide than any single rule of thumb.
Why is my CAGR different from the total return divided by years?
Because CAGR accounts for compounding, while a simple division assumes growth happened in equal flat slices every year, which understates how compounding actually works when returns build on previous growth.
Can CAGR be negative?
Yes — if your current value is lower than your purchase value, both the total return and CAGR will show as negative, reflecting a loss over the period rather than a gain.
Does this work for property as well as funds or shares?
Yes — the same calculation applies to any asset with a known starting and current value, including a property, provided you're comfortable treating the current value as an estimate rather than a confirmed sale price.
Should I subtract fees before calculating my return?
Ideally yes — using your net (after-fee) starting and current values gives a more accurate picture of what you actually earned, since gross figures that ignore platform and fund charges can overstate your real return.
How many years of data should I use for a meaningful CAGR?
Longer periods generally give a more meaningful, less noisy figure — a CAGR calculated over just a few months can be heavily skewed by short-term market movements that say little about a genuine long-term trend.