Inflation Calculator
What inflation does to your money: future prices, and what today's cash will still buy.
The two sides of the same coin
At 3% inflation for 20 years, something that costs $1,000 today will cost about $1,806, and $1,000 kept in cash will only buy what $554 buys today. Both numbers come from the same factor, (1 + rate)years; one multiplies, the other divides.
Rule of 72
Divide 72 by the inflation rate to estimate how long prices take to double: at 3%, about 24 years; at 6%, about 12. The same rule works for investment returns, which is exactly why holding long-term savings in cash loses to inflation: the doubling works against you.