Tools · Investing
Real Return Calculator
What your return is actually worth once inflation is taken out — and what a sum of money will really buy in ten or twenty years.
The headline figure on your statement, before inflation.
Use the published CPI rate for the period you are measuring.
Enter a nominal return and an inflation rate to see what you actually made.
Is your portfolio keeping ahead of inflation?
Our advisers can review your holdings, currency exposure and charges against a real-return objective rather than a headline one.
What this calculator does and who it's for
There are two numbers attached to any investment: the one on the statement, and the one that tells you whether you are better off. This calculator converts the first into the second. It takes a nominal return and the inflation rate over the same period, and returns the real return — the change in what your money can actually buy.
It is aimed at anyone holding long-term wealth, and it matters most in two situations that look very different on a statement. The first is cash: a deposit account paying a healthy headline rate during an inflationary period is usually losing purchasing power every month while appearing to grow. The second is a long horizon, where a difference of one or two percentage points in the real rate compounds into an enormous difference in outcome over twenty or thirty years.
Why the exact formula, not the shortcut
Almost everyone calculates a real return by subtracting inflation from the nominal figure. That is an approximation of the correct relationship, which divides:
Real return = ((1 + nominal) ÷ (1 + inflation) − 1) × 100
The shortcut is close enough when both numbers are small. At 7.5% against 3.2% inflation it overstates the real gain by about 0.13 percentage points — immaterial for most purposes. But the error grows with the numbers: at 20% nominal against 15% inflation, subtraction claims 5% when the true figure is 4.35%, an overstatement of roughly 13% of the gain. Because the environments where real returns matter most are precisely the high-inflation ones, this tool uses the exact form and shows the subtraction result beside it so you can see the difference for your own inputs.
Purchasing power over a long horizon
Enter an amount and a number of years and the calculator adds a second dimension: what the money will be worth in today's terms. This is the same operation economists use to convert nominal GDP into real GDP, applied to your own balance. At 3% inflation, £100,000 in ten years buys roughly what £74,400 buys today — a quarter of the purchasing power gone without a single figure on the statement falling.
When you supply a nominal return as well, the table shows both the projected balance and that balance restated in today's money on adjacent rows. The gap between those two figures is the clearest illustration of why a long-term plan built on nominal targets can quietly fail: a pot that hits its headline number may still fall well short of the standard of living it was meant to fund.
Choosing the right inflation figure
The published CPI rate for the matching period is the sensible default. It is the figure central banks target and the one index-linked instruments reference. Two qualifications are worth carrying. First, CPI measures a fixed basket, so it cannot capture the way households substitute toward cheaper alternatives when prices rise — a known reason it tends to overstate the true increase in the cost of living. Our Macro Formula Lab lets you build CPI from basket costs directly and see the mechanism.
Second, the national figure may not be your figure. If you live in one country, earn in a second and hold assets in a third — the ordinary position for many expatriates — your personal inflation rate depends on where you actually spend, and the currency you spend in. An investor drawing income in one currency from assets denominated in another is exposed to both inflation and exchange-rate movement, and the two can compound. That is a question worth putting to an adviser rather than a calculator.
Limitations, and what to do with the result
This tool works only on what you give it. It has no market data and makes no forecast; the purchasing-power projection assumes one constant inflation rate across the whole period, which is a modelling convenience rather than a description of reality. It does not model tax or charges, both of which bite before inflation does — so enter a return that is already net of both if you want a realistic figure. And a real return is a measure of the past or an illustration of an assumption, never a prediction of what any investment will deliver.
Used properly, the number tells you one thing very clearly: whether your wealth is growing or shrinking in terms that matter. If the answer is negative, that is worth acting on — and the appropriate action depends entirely on your circumstances, horizon and tax position. Explore the wider set in our financial tools, read the context in our investment guides, or speak to an adviser about your own position.
Important — This calculator performs arithmetic on figures you supply. It holds no market data, makes no forecast, and expresses no view on any investment. The purchasing-power projection assumes a single constant inflation rate for the whole period, which no real period delivers. Returns entered gross of tax and charges will overstate what you keep.
This tool is a general illustration based on the figures you enter. It does not constitute financial, investment, tax or legal advice, and the results are estimates rather than guarantees. Global Investments is not authorised or regulated by the Financial Conduct Authority. Where the amounts involved are material, take advice from a suitably qualified professional in each relevant jurisdiction before acting.
Related tools & guides
- Macro Formula Lab — the full set — GDP, CPI, unemployment and the multipliers
- Investment services — building a portfolio against a real-return objective
- Investment guides — markets, asset classes and strategy
- Portfolio Yield Calculator — the income side of the same portfolio
- Retirement Calculator — where real returns compound over decades
- All financial tools — the full calculator library
Real returns and inflation — common questions
6 questions
What is a real return?
A real return is what is left of an investment return once inflation has been taken out — the increase in what your money can actually buy, rather than the increase in the number on your statement. If a portfolio returns 5% in a year when prices rise 5%, the nominal return is positive but the real return is approximately nil: you finish the year able to buy the same basket of goods you could buy at the start. Real return is the figure that matters for any long-term goal, because goals are denominated in things — a retirement income, a property, school fees — rather than in pounds.
Link to this questionWhy does this calculator not simply subtract inflation from the return?
Because subtraction is an approximation, and it gets worse as inflation rises. The exact relationship divides rather than subtracts: real = ((1 + nominal) ÷ (1 + inflation) − 1). At 7.5% nominal and 3.2% inflation, subtracting gives 4.3% while the exact form gives 4.17% — a difference small enough to ignore in conversation. At 20% nominal against 15% inflation, subtracting gives 5% while the true figure is 4.35%, which is a 13% overstatement of the gain. The calculator shows both figures side by side so the size of the shortcut is visible rather than hidden.
Link to this questionCan a real return be negative when the nominal return is positive?
Yes, and this is the most common reason people misjudge how a holding is performing. Cash paying 4.5% in a year when inflation runs at 6% delivers a real return of about −1.4%: the balance grows every month while its purchasing power shrinks. Nothing on the statement signals this, because statements are denominated in currency rather than in purchasing power. Periods of elevated inflation produce negative real returns across cash and much of the bond market simultaneously, which is why the distinction matters far more in some environments than others.
Link to this questionWhich inflation rate should I use?
For most purposes, the published CPI rate covering the same period as your return. That is the standard reference, the figure central banks target, and the one used in index-linked contracts. Two caveats are worth knowing. CPI tracks a fixed basket, so it cannot capture households substituting toward cheaper alternatives when prices rise — which means it tends to overstate the increase in the cost of living. And your personal inflation rate may differ substantially from the national figure depending on where you live and what you spend on, which matters particularly for expatriates whose costs sit in a different currency and economy from the index they are reading.
Link to this questionWhat does the purchasing power figure show?
It restates a future sum in today's money. Enter an amount, an inflation rate and a number of years, and it divides the amount by (1 + inflation) raised to the power of the years — the same operation as converting nominal GDP into real GDP, applied to your own money. £100,000 in ten years at 3% inflation buys roughly what £74,400 buys today. When you also enter a nominal return, the table grows the pot at that return first and then deflates it, so you can see the projected balance and its real purchasing power on adjacent rows. That gap is usually the most informative number on the page.
Link to this questionDoes this account for tax and charges?
No. The calculation runs on the return figure you enter, so whatever you supply is what it works with. Tax and product charges both reduce returns before inflation is applied, and the order matters: a 6% gross return reduced by 1% in charges and then taxed leaves considerably less to be eroded by inflation than the headline suggests. For a realistic picture, enter a net-of-charges, net-of-tax return rather than a gross one. Your own tax position depends on residence, domicile and the wrapper the investment sits in, and warrants advice. Global Investments is not authorised by the Financial Conduct Authority.
Link to this question