See how the purchasing power of money changes over time: convert a past amount into today’s money, or project what today’s money will be worth years from now.
Past mode treats the amount as money from the past and grows it forward at the average rate, so you see what it is worth in today’s money.
Future mode treats the amount as money you hold today and shows what its buying power shrinks to after the years ahead, at the assumed rate.
Advanced: currency symbol
| Year | Equivalent value | Buying power vs start |
|---|
Each row applies one more year of compound inflation. Buying power is shown as a percent of what the starting amount could buy.
The line bends rather than running straight, because inflation compounds: each year’s change is applied on top of the previous year.
For beginners: how to read this result
To get a result, choose one of the preset scenarios or enter your own figures. Pick a calculation direction first, then enter the amount, the number of years and the average annual inflation rate. The headline returns the equivalent value, and a table and chart show the year-by-year path.
The two calculation modes
The direction toggle changes what the calculator solves for and relabels every field accordingly.
- Past value in today’s money — you enter an amount from the past, how many years ago it is from, and the average annual inflation rate since then. The calculator grows the amount forward and returns what it is worth in today’s money.
- Future value of today’s money — you enter an amount you hold today, how many years ahead to project, and the inflation rate you assume. The calculator returns the future buying power of that money expressed in today’s money, and the buying power it loses.
How the math works
Inflation compounds, so the calculator does not simply multiply by the rate once. It applies a yearly factor equal to one plus the rate divided by 100. In past mode the amount is multiplied by that factor once for every year, so the equivalent today equals the amount multiplied by the factor raised to the power of the number of years. In future mode the amount is divided by that factor once per year, because the same number of units of money buys a little less each year. The total inflation shown is the factor raised to the number of years, minus one, written as a percent.
Why the rate is your input
No historical price data is built into this tool. Inflation differs by country, by year and by the basket of goods measured, so the average annual rate is something you enter yourself. That lets you test a cautious assumption and an optimistic one, and see how much the answer moves. Long-run averages are commonly in the low single digits, but the choice is yours.
The year-by-year table and curve
The table lists every year with the running equivalent value and the buying power as a percent of the start, so you can read the figure at any intermediate year. The line chart draws the same series. The line bends instead of running straight, which is the clearest way to see that inflation compounds: each year’s change is applied on top of all the years before it.
What is not included
This is an estimate. It uses a single constant average rate for the whole period, while real inflation varies from year to year. It does not account for wage growth, investment returns, taxes or currency conversion. Treat the result as a planning guide rather than an official figure.