Some of you may know the Rule of 72 (or 70): If you have money compounding interest at R% per year, it doubles in value after roughly 72/R years (for single-digit R). A handy rule for assessing how much you can expect of your investments/loans.
Some of you may know the Rule of 72 (or 70): If you have money compounding interest at R% per year, it doubles in value after roughly 72/R years (for single-digit R). A handy rule for assessing how much you can expect of your investments/loans. But there's also a Rule of 125: If you pay in a fixed amount of money into something that compounds at R% per year, it doubles in total value after roughly 125/R years (again, for small R). Handy for assessing long-running regular-deposit savings plans.