Educational guide · Updated 6 de October de 2026 · 8 min read
Nominal return describes a change measured in money. Real return adjusts that change for prices to examine purchasing power. The distinction matters when balances grow over several years: a larger number may finance the same purchase, a bigger purchase or a smaller one, depending on how prices move. Neither measure replaces the other. Nominal balances help plan future payments, while real balances compare buying power with a reference date. Always identify that date and the costs reflected in the figure. Otherwise, two accurate numbers can still produce a misleading comparison because they answer different questions.
The exact relationship uses growth factors
With a 5% annual return and 3% inflation, the nominal factor is 1.05 and the price factor is 1.03. The real factor is 1.05 divided by 1.03. Subtracting one gives a real return of approximately 1.94%. Simply subtracting three from five gives 2%, a close approximation here but not the exact relationship. The difference becomes greater at higher rates. Use rates covering the same period and check that their conventions are compatible before dividing them. Mixing a monthly inflation figure with an annual investment return would create a result with no coherent interpretation.
Positive money growth can still mean less buying power
Imagine a 2% return and 4% inflation. The amount of money rises, but the real factor, 1.02 divided by 1.04, is below one. Purchasing power falls by approximately 1.92%. That does not mean money was withdrawn from the account: nominal balance and real value describe different effects. Displaying only the cash gain can leave an incomplete impression. Displaying only real value may also be insufficient when you need the number of currency units available to settle an obligation at a particular future date. Keep both figures with clear labels rather than selecting whichever looks more reassuring.
Costs and taxes require another layer
An advertised return may be before or after particular costs. Establish what it includes before subtracting charges again. A known annual proportional charge can be explored, but subtracting percentages does not always reproduce the exact contract or timing of collection. Taxes depend on rules, product, residence and realisation timing. Selecting a country does not supply one universal tax percentage. Keep a simulation clearly labelled before tax, and use a separate documented calculation when the relevant conditions are known. A simplified educational model should make missing inputs visible instead of quietly treating unknown costs as if they did not exist.
Contributions and returns are not interchangeable
An account rising from 5,000 to 7,000 while you deposit 1,800 has not generated a 40% investment return. Much of the increase is new money. Separating contributions from growth is the first step; calculating a return on cash flows also requires their dates. Withdrawals create the same issue in reverse. Balance growth is not automatically investment performance when money moves in and out. Simuily's annual table separates amounts, but does not calculate a personal historical return weighted by every transaction date. Use an appropriate cash flow performance method when that is the question you need to answer.
Avoid adjusting for inflation twice
You can project a nominal balance and then divide by the accumulated price factor. Alternatively, a fully consistent model can be constructed in real terms. Do not apply a real rate and then deduct inflation again from the same result. With contributions, also decide whether deposits are constant in nominal money or purchasing power: those are different cash flows. Simuily holds monthly contributions constant in nominal terms and also expresses the final balance in today's money. Preserve that convention when comparing another tool's output. An apparent discrepancy may come from different contribution assumptions rather than an incorrect formula.
Frequently asked questions about the two measures
Is real return a better basis for comparing investments? It can connect results with purchasing goals, but risk, access, costs and taxes still matter. Can past inflation be used for a future horizon? It can be an explicitly identified assumption, not a certainty of repetition. Does the same percentage always produce the same result with deposits? Frequency and deposit timing matter. How should a comparison be displayed? Separate capital, contributions, nominal balance, growth and inflation adjusted value, then state the reference date and assumptions. The following workshop uses constant numbers to explain these relationships, rather than describing a product or guaranteeing that inflation beating returns are available without risk.
Practical workshop: contributions, growth and prices
This workshop applies the guide to a hypothetical example. Amounts are currency units and rates are assumptions, not available offers or forecasts. We start with 5,000.00, add 100.00 at the end of every month and continue for 12 years. The assumed effective annual return is 5% and constant annual inflation is 3%. Reproduce these inputs in the compound interest calculator, then replace them with figures relevant to your own objective. Keeping assumptions visible lets you compare scenarios without confusing a changed input with an actual improvement in financial conditions.
By the end, total contributed money is 19,400.00. That is starting capital plus 144 monthly deposits. The calculated nominal balance is 28,513.70, so the difference from contributed money is 9,113.70. This difference is assumed growth before any costs or taxes not reflected in the rate. It is not a guaranteed payment. Subtracting contributions from the balance remains useful even when the difference looks modest: it prevents your own saving effort from being presented as investment performance. The calculation also makes clear which part of the result depends on assumptions outside your direct control.
First check: remove the growth assumption
Run the calculation again with a zero rate. The closing balance should equal 19,400.00. Keep duration and contributions unchanged so that only one variable moves. This second calculation shows how much of the objective would be financed by your own deposits. A small difference from the original result means contributions account for much of the balance over this horizon. A large difference means the original outcome relies more heavily on assumed growth. Neither observation chooses a suitable product for you: access, risk and actual account conditions still need to be considered separately.
Now change only the monthly contribution, adding 50. At the original rate, the closing balance becomes 38,280.91. Of the increase, 7,200.00 is additional money you would contribute yourself; the remainder is assumed growth on those extra deposits. Before adopting the change, identify where that extra 50 would come from each month. Moving a calculator control is easy, while a real budget must continue to cover essential spending and other commitments. A higher scenario is useful only when its contribution can be repeated in your actual circumstances without borrowing elsewhere to fund the deposits.
Second check: express the balance in today's money
At the selected inflation rate, the final 28,513.70 would represent approximately 19,998.93 of present purchasing power. The calculation divides the future balance by one plus inflation raised to the number of years. It does not subtract the annual inflation percentage just once. This adjustment helps compare amounts at different dates, but it assumes a constant general rate. The particular price of a home, course or service can follow another path. If an updated quotation is available for the thing you want to buy, use that information to review the target as well.
Retain both nominal and real figures, with different labels. The nominal figure answers how much money the model produces at the final date. The real figure describes its approximate buying power relative to the starting date. Do not add them together: they describe the same balance from two perspectives. Also avoid using the real figure as nominal starting capital in a later simulation without checking the units. This distinction becomes particularly useful when joining several stages together or comparing a budget quoted at today's prices with money expected to be available several years from now.
Use the annual table to review progress
Inspect year zero, year one and the last year. The first is the starting position; the next includes twelve deposits, and the last covers the complete horizon. Between consecutive rows, the balance increase contains both new saving and growth. Record those components separately. When exporting the CSV, retain the calculation date, currency and assumptions. At a later review, use the actual balance on that date and the remaining duration. Avoid counting past contributions again as though they were new money still available to deposit. A clear record is more informative than remembering only the largest projected balance.
Questions the workshop cannot settle automatically
Can you withdraw the money when needed? Check the account or investment conditions. Can the balance lose value? That depends on the product; this constant growth curve does not represent market fluctuations. How much remains after tax? You need the relevant tax residence, income category, payment timing and applicable rules. Selecting a country provides context and reference links, but it does not calculate a tax assessment. What should you test next? Choose one input linked to your decision, such as the date, contribution or target budget, and keep the previous scenario so you can explain precisely why the result changed.