Regra de 72
Calcule quanto tempo leva para dobrar um investimento.
Entrada
Anos para Dobrar
O investimento dobra em 2036
Divida 72 pela sua taxa de retorno anual para estimar os anos necessários para dobrar seu investimento.
Cronograma de Duplicação
@ 7% retorno anual
Comparação de Ativos
Impacto da Inflação
A Regra de 72 também mostra com que rapidez a inflação corrói o poder de compra. Com inflação anual de 3%, os preços dobram em apenas 24 anos.
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Using the Rule of 72 to Estimate Doubling Time
Visão Geral
The Rule of 72 is a quick mental shortcut for how long it takes an investment to double at a fixed annual return: just divide 72 by the rate. It is remarkably accurate for typical rates and great for sanity-checking growth without a spreadsheet. This calculator applies it instantly, and also works in reverse to find the rate needed to double in a given time.
Como usar (passo a passo)
- 1
Enter the annual rate
The expected yearly return or interest rate as a percentage.
- 2
Read the doubling time
The tool divides 72 by the rate to estimate years to double.
- 3
Or solve for the rate
Enter a target number of years to see what annual rate doubles your money in that time.
Como Funciona
Years to double ≈ 72 ÷ annual interest rate (as a percent). At 8%, money doubles in about 9 years; at 6%, about 12 years. The 72 works because it closely approximates the exact logarithmic doubling formula for rates between roughly 4% and 15%. To find the required rate instead, divide 72 by the number of years you have.
Quando usar
Quickly estimating how fast savings will grow. Comparing the long-term impact of different return rates. Showing how inflation erodes purchasing power (how fast prices double).
Perguntas Frequentes
Very close for rates between about 4% and 15%. At higher or lower rates the approximation drifts slightly from the exact figure, but it remains a useful estimate.
Notas Importantes
The Rule of 72 is a rough mental-math approximation, not investment advice. Real returns are not fixed and are not guaranteed — consult a licensed financial advisor before making investment decisions.