Rule of 72
A mental shortcut: divide 72 by the annual interest rate to estimate how many years it takes for money to double. At 6% the answer is 12 years; at 9% it is 8 years. It is surprisingly accurate for rates between 2% and 15%.
A mental shortcut: divide 72 by the annual interest rate to estimate how many years it takes for money to double. At 6% the answer is 12 years; at 9% it is 8 years. It is surprisingly accurate for rates between 2% and 15%.