Rates & growth
Inflation purchasing-power calculator
Inflation is compounding in reverse: the figure stays, purchasing power shrinks. Three inputs show a sum's time value.
Needed in 10 years for equal purchasing power
13,439.16
Today's sum will really buy
7,440.94
Purchasing-power loss
−25.59%
Year by year
| Year | Needed for equal power | Real worth of today's sum |
|---|---|---|
| 1 | 10,300 | 9,708.74 |
| 2 | 10,609 | 9,425.96 |
| 3 | 10,927.27 | 9,151.42 |
| 4 | 11,255.09 | 8,884.87 |
| 5 | 11,592.74 | 8,626.09 |
| 6 | 11,940.52 | 8,374.84 |
| 7 | 12,298.74 | 8,130.92 |
| 8 | 12,667.70 | 7,894.09 |
| 9 | 13,047.73 | 7,664.17 |
| 10 | 13,439.16 | 7,440.94 |
Two directions, one formula
'Money needed in N years to buy what this buys today' = amount ×(1+CPI)^years; 'what today's sum will really buy then' = amount ÷(1+CPI)^years. The shrinkage rate is 1 −(1+CPI)^(−years).
Set it against your return targets: nominal yield minus inflation is the real gain. At 3% CPI, prices roughly double in 24 years and idle cash loses about half its power.
Frequently asked
What inflation rate should I enter?
Use the official CPI YoY (recently in a 0–3% band) or a higher personal feel for stress-testing. It is an assumption, not a forecast.
Why does 'needed' outgrow the shrinkage?
One multiplies by (1+c)ⁿ, the other divides — compounding is asymmetric: at 3% for ten years, needed +34% while today's money buys −26%.
Can it estimate past inflation?
Set years to the span and the rate to the period's average CPI for an approximation. For official history, use national statistics.
How does this compare with investment return?
Real return ≈ nominal − inflation (exactly: (1+nominal)/(1+CPI) − 1). At 5% nominal and 3% CPI, purchasing power grows about 1.9%/yr.
Constant-rate estimate; official CPI baskets may differ from your lived costs. For reference only.