TheCalculatory
Financial · Everyday Money Formula verified

Investment Calculator

Project the balance forward the way Compound Interest does, then see what it's actually worth in today's purchasing power once inflation is subtracted the correct way.

Inputs
$
$0$100k$200k
$
$0$2,500$5,000
%
0%7.5%15%
%
0%5%10%
years
1yr25yr50yr
On-screen number pad
Tap to type into the highlighted field
Projected balance
$144,572.72
3.88% real return
Total contributed
$58,000.00
Growth earned
$86,572.72

Step-by-step proofCheck by hand
This is a projection based on a constant assumed return, which real markets never deliver — actual returns vary year to year and can be negative. This is not investment advice, and past or assumed returns are not a guarantee of future performance. Consult a licensed financial advisor before making investment decisions.
Visual breakdown

Contributed vs. growth

Contributed Growth

The bar shows what you put in versus what the market added, as shares of the projected nominal balance — the same two numbers as the result panel, drawn to scale.

Nominal vs. real return

The nominal balance is what your account statement will actually show — the raw dollar total after compounding your contributions at the expected return. The real return strips out inflation, answering a different question: how much more purchasing power will that money actually have, in today's dollars?

The correct way to remove inflation from a rate is not subtraction. Dividing one growth factor by the other — the Fisher equation — gives the exact answer; subtracting the two percentages is a shortcut that's only approximately right, and drifts further from correct as either rate rises.

This is a projection, not a promise
Markets don't deliver a constant return every year — some years are sharply negative. Treat this as one scenario among many, not a forecast.
Fees and taxes aren't included
Fund fees, advisor fees, and taxes on gains or dividends all reduce real-world returns and aren't subtracted here — factor them into the return rate you enter.

The formulas

1 + real rate = (1 + nominal rate) ÷ (1 + inflation rate)

Nominal balance grows the same way Compound Interest projects it — see that page for the full compounding formula.

Worked example

$10,000 invested up front, plus $200 a month, at an expected 7% annual return over 20 years, grows to a nominal $144,572.72 — $58,000 of that from contributions, the rest from growth. At 3% expected inflation, the exact real return is 3.88% (the shortcut subtraction would say 4%), and that nominal balance is worth about $80,046.41 in today's purchasing power.

Frequently asked questions

Why isn't the real return just the nominal return minus inflation?
Subtracting is a common shortcut, but it's only approximately right at low rates. The exact relationship — the Fisher equation — divides one growth factor by the other rather than subtracting the percentages: (1 + real) = (1 + nominal) ÷ (1 + inflation). At 7% nominal and 3% inflation, the shortcut says 4%, while the exact figure is 3.88%. The gap widens as either rate rises.
What return rate should I use?
There's no single right answer — it depends on what you're invested in and your own risk tolerance. A long-run US stock market average is often cited around 7–10% before inflation, but any individual year can be sharply higher or lower, and past performance doesn't predict future returns. Try a few different rates to see a range of outcomes rather than trusting one number.
How is this different from the Savings and Compound Interest calculators?
All three share the same underlying growth math. Compound Interest projects a balance forward with no goal in mind. Savings solves for the time or contribution needed to hit a dollar goal. This one adds the inflation layer on top of a Compound-Interest-style projection, because for a multi-decade investment, what the money is actually worth later matters more than the nominal number.
Does this account for investment fees or taxes?
No. Management fees, fund expense ratios, and capital gains or dividend taxes all reduce real-world returns and are not subtracted here. A fund charging a 1% annual fee, for instance, effectively lowers the return rate you should enter by roughly that amount.
Sources and method
  • Growth projection — the same published compound-interest mathematics as the Compound Interest Calculator.
  • Real (inflation-adjusted) return — the Fisher equation, standard published economics: (1 + real rate) = (1 + nominal rate) ÷ (1 + inflation rate).
Last reviewed: 19 Sep 2026 Sources last verified: 19 Sep 2026 Results use the assumptions explained on this page. Report an error How we check calculations

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