Investment Return Calculator

How to Use the Investment Return Calculator

Four numbers turn a portfolio statement into something you can compare against anything else. The one people leave out is the third — money added along the way — and leaving it out is what makes a mediocre investment look excellent.

1. Enter the starting value. What the holding was worth when you bought it, before any later top-ups.
2. Enter everything you added since. Every contribution, deposit or reinvested cash injection. If you skip this, the calculator will treat that money as growth and report a return that never happened.
3. Enter the value now. The current market value, after fees if your platform deducts them from the balance.
4. Enter the years held. Decimals are fine — 2.5 for thirty months. This is what converts a total return into an annualised one, and without it you cannot compare two investments held for different lengths of time.

The headline figure is the total return on everything you put in. The second tile is the annualised version, which is the number worth quoting. The table shows what steady growth at that annualised rate would have looked like — a smooth line through a lumpy reality.

Investment Return Formula

Total return is straightforward. Annualising it is where the useful work happens.

One simplification is baked in: contributions are treated as though they were all present from the start. That understates the annualised return when most of the money arrived late, and overstates it when most arrived early. A money-weighted return (IRR) fixes this but needs the date of every contribution, which is more bookkeeping than most people have to hand.

Example

A holding bought for $10,000, topped up by $6,000, now worth $24,500 after 7 years

1. Total invested: 10,000 + 6,000 = $16,000.
2. Profit: 24,500 − 16,000 = $8,500.
3. Total return: 8,500 ÷ 16,000 × 100 = 53.125%.
4. Money multiple: 24,500 ÷ 16,000 = 1.53125.
5. Annualised: 1.53125^1/7 − 1 = 1.062760 − 1 = 6.276% a year.

The same 53% over three years instead of seven

Identical money in, identical money out — but held for three years rather than seven. The total return is still 53.125%. The annualised return is 1.53125^1/3 − 1 = 15.26% a year. Same headline, wildly different investment. This is why the annualised figure is the one that belongs in any comparison and the total return is the one that belongs in a marketing brochure.

Now try leaving the contributions out. Compare $10,000 with $24,500 and you get a 145% total return and 13.6% a year — more than double the honest figure, purely by forgetting to count $6,000 of your own money.

Which Return Figure to Quote

Three numbers on this page answer three different questions, and mixing them up is the most common error in amateur portfolio reporting.

The annualised figure is the only one that travels. A 53% return sounds better than a 30% return until you learn the first took seven years and the second took two — 6.3% a year against 14.0% a year. Whenever someone quotes a return without a time period attached, the time period is the part worth asking about.

Read the sign carefully on losses too. A holding that falls 50% needs to rise 100% to get back to even, because the recovery is calculated on the smaller base. That asymmetry is why avoiding large drawdowns matters more to a long-run result than capturing large gains.

One more reading habit: compare the money multiple against the number of years before you react to a percentage. A 1.53× multiple over seven years and a 1.53× multiple over two years are the same multiple and completely different investments, and the multiple is the figure most likely to appear in a headline precisely because it hides the timeline. Whenever a return is quoted without a period attached, treat the missing period as the most interesting part of the claim.

What the Calculation Cannot See

What this calculator cannot see, and what to do about it.

Timing of contributions. If you put $5,000 in last month, treating it as though it had been invested for seven years drags the annualised figure down unfairly. When contributions are large relative to the starting value and recent, run the calculation on the original holding alone as a sanity check.

Dividends and income. If dividends were reinvested they are already in the ending value and nothing needs doing. If they were paid out to you, add them to the ending value — otherwise you are measuring only capital growth and understating the total return.

Fees and tax. Platform charges deducted from the balance are already reflected. Charges paid separately, and any tax on gains or income, are not. A 1% annual fee turns a 6.3% return into a 5.3% one, which over twenty more years is roughly a fifth of the final balance.

Inflation. A 6.276% nominal return with 2.5% inflation is about 3.7% real. For anything held longer than five years, that is the figure that tells you whether you actually got richer. The inflation calculator makes the adjustment, and the CAGR calculator handles the pure growth-rate case where there were no contributions at all.

Withdrawals. If you took money out during the period, the tool will understate your return, because that money is missing from the ending value without having been removed from the invested total. Add withdrawals back to the ending value to get a like-for-like figure, or subtract them from contributions if they were effectively a refund of capital.

Currency. A holding bought in one currency and valued in another mixes an investment return with an exchange-rate movement. Both are real money, but they are different decisions, and separating them tells you whether you picked the asset well or simply got lucky on the rate.