Translate money across time at an inflation rate you choose: what a future sum will cost, and what today's money will actually buy after years of rising prices. Runs entirely in your browser — your numbers never leave this device.
| Year | Future cost | Purchasing power (today's money) |
|---|---|---|
| Year 1 | $103.00 | $97.09 |
| Year 2 | $106.09 | $94.26 |
| Year 3 | $109.27 | $91.51 |
| Year 4 | $112.55 | $88.85 |
| Year 5 | $115.93 | $86.26 |
| Year 6 | $119.41 | $83.75 |
| Year 7 | $122.99 | $81.31 |
| Year 8 | $126.68 | $78.94 |
| Year 9 | $130.48 | $76.64 |
| Year 10 | $134.39 | $74.41 |
The inflation rate is your assumption — no official forecast is baked in. Change it to see how sensitive the answer is.
Inflation is compound growth applied to prices instead of savings, so the maths is identical and runs in both directions. Forward: an amount multiplied by (1 + i) once per year gives what it will cost in the future. Backward: dividing a future amount by the same factor gives its value in today's purchasing power — the figure that tells you what a projected savings balance or a future salary will actually feel like.
The rate is entirely your assumption. This calculator contains no built-in CPI data, no official statistics and no country figures — deliberately, because published inflation varies by country and year, past rates do not set future ones, and a baked-in number would smuggle in an assumption while pretending to be a fact. You enter the rate you want to test, the page states it back in the results, and running two or three plausible rates shows the range of honest answers.
Because inflation compounds, small rate differences widen dramatically over long horizons. At 2% for 20 years, $100 of today's goods costs $148.59; the same basket at higher rates costs far more, and cash held uninvested loses purchasing power on exactly the same curve in reverse. The year-by-year figures are shown so the steady erosion is visible rather than summarised into a single startling total.
Because there is no single correct rate to bake in: official inflation differs by country, changes every year, and measures the past rather than the future period you are planning over. A built-in figure would look authoritative while being the wrong number for most users and most purposes. The rate here is explicitly your assumption, shown in the results, so the projection is honest about what it rests on.
That choice is yours, and the sensible approach is a range rather than a point: run the calculator at a low rate, a moderate rate and a high rate for your horizon and read the spread. Long-run averages in many economies sit somewhere in the low single digits, but your period and your country may differ — the tool's job is the arithmetic for whichever rates you supply.
They are the same calculation run in opposite directions. Future cost asks: goods costing $100 today will cost how much in 10 years at 3%? Answer ≈ $134.39. Purchasing power asks: $100 in cash kept for those 10 years will buy what in today's terms? Answer ≈ $74.41 of today's goods. Both use the factor (1.03)^10 ≈ 1.34392 — multiplied in the first, divided in the second.
It reduces what the projected balance is worth. A projection that reaches $50,000 in 10 years at 3% inflation has the purchasing power of 50,000 / 1.34392 ≈ $37,205 in today's money. A rough shortcut used by planners is to project growth at a rate net of inflation (growth rate minus inflation rate) to get an approximate real-terms answer directly.
Yes — falling prices are called deflation, and the formula handles a negative rate correctly: at −2% for 10 years, $100 of goods would cost 100 × (0.98)^10 ≈ $81.71, and cash gains purchasing power. Sustained deflation is uncommon, but the maths does not assume it away.
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