Inflation Calculator
Compare purchasing power across years with approximate CPI annual averages, or project how today’s amount changes at a chosen inflation rate.
Calculate
Result
The formula
Historical: Amount_to = Amount_from × (CPI_to ÷ CPI_from). Forward: Future = Present × (1 + rate)^years. Average annual rate ≈ (factor)^(1/years) − 1.
Worked example
- $10,000 in 1990 → CPI≈130.7; in 2025 CPI≈321.0
- Factor ≈ 321.0/130.7 ≈ 2.46 → ≈ $24,629 in 2025 terms
- Average ≈ +2.6%/year over 35 years; buying power ≈ 41% of 1990
Result: $10k (1990) ≈ $24.6k (2025) CPI-adjusted
How inflation adjustment works
Price indexes turn “how many dollars” into “how much buying power.”
Past prices (CPI)
We multiply your amount by the ratio of annual-average consumer price indexes for the two years. Series are teaching approximations aligned with national CPI publications — not a substitute for official downloads for contracts.
Future projection
Compounding at a constant annual rate shows how many nominal units you need later to keep pace. Real investment returns require subtracting inflation separately.
Limits
Baskets change; local prices diverge from the national average; housing and healthcare can move faster. Use country-specific official indexes when precision matters.
Interesting facts
Rule of 72
At ~3%/year inflation, prices roughly double in 72÷3 ≈ 24 years — a quick mental check.
Nominal vs real
A 5% raise with 3% inflation is about 2% real. Always compare rates on the same basis.
CPI baskets differ
Your groceries and rent may inflate faster or slower than the headline index.
Deflation years
If the later index is lower, adjusted amounts shrink — money gained purchasing power.
Not an investment return
This adjusts for prices — it does not model stock or bond returns.
Frequently asked questions
Choose Past prices, enter the amount and both years. We multiply by the ratio of annual CPI values for this country series.
Set from-year to 1990 and to-year to a recent year (e.g. 2025). The result applies the CPI ratio to $10,000.
Enter today’s amount, an annual inflation rate, and years. FV = amount × (1+rate)^years.
It is an approximate teaching CPI series. Download official tables from your national statistical office for contractual or research precision.
The geometric average: (CPI_to ÷ CPI_from)^(1/years) − 1 — the constant yearly rate that compounds to the same total factor.
CPI tracks a broad basket. Your personal mix of housing, food, and healthcare can rise faster than the average.
References
- Consumer Price Index (CPI) Official CPI overview and data access.
- CPI inflation calculator BLS’s own dollar-conversion tool.
- Inflation concepts Educational materials on inflation and purchasing power.