Calculadora de inflação
The detailed guide below is currently available in English.
How this inflation calculator works
Inflation compounds. A good that costs A today, with prices rising at an average rate g per year, costs A × (1 + g)n after n years. Running the arithmetic backwards answers the mirror question — what did a today's price cost n years ago — by dividing instead of multiplying.
Constant rate versus real CPI
This tool uses a single average rate that you enter, which keeps the arithmetic transparent and works for any country or period. Real consumer price indexes move unevenly — an official CPI series may run above or below a flat average for years at a time — so treat the results as solid estimates rather than historical quotes.
Perguntas frequentes
What inflation rate should I enter?
A common choice for long-run planning in the U.S. is about 3% per year, close to the historical average. For other countries or periods, use the average annual change of that consumer price index.
Why do my results differ from an official CPI calculator?
Official calculators splice together actual year-by-year index values, while this tool applies one constant rate. Over long spans the two converge on similar answers, but individual years can differ noticeably.
Can inflation be negative?
Yes — falling prices are called deflation. This calculator accepts rates of zero and above; enter 0% to see prices held flat over the period.