If there's one thing you want to be sure of when it comes to investing and retirement planning, it's that you'll have enough money to meet your financial needs over the long-term.当你考虑到投资和退休计划时，有一件事是你想要知道的，那就是你是否有足够的钱去满足你的长期财务需求。
Part of retirement planning and investing involves making calculations to see how likely--and how quickly--your money is to grow over time. Compound interest is an amazing thing, and the Rule of 72 is a simple way to quickly estimate how long it will take your investment to double in size, assuming you reinvest any dividends. It's a helpful way to put the time value of money into perspective as you map your retirement and investing strategies.投资和退休计划的一个环节就是去计算你的财富的未来增值，是涨是跌、是快是慢。复利是一个神奇的东西。你的投资需要多长时间才能翻番？72法则是快速估计所需时间最简单的方法（假设你所有的利息也再投入到投资中）。当你在规划退休计划和投资战略时，它是一个计算货币的时间价值的有效工具。
Another upside is that utilizing this rule is relatively simple. The only piece of information you need to complete the Rule of 72 calculation is the annual rate of return on your investment. Although, you'll probably also want to use a calculator to run the numbers.使用72法则也非常的简单，你唯一需要的数据就是投资的年回报率。当然，你还是希望用计算器去跑数据。
One thing to note: the Rule of 72 works best for investments that have a fixed rate of return. While most investments don’t have a fixed rate of return over a long period of time, you can use an average estimate to get a pretty good idea of how long it will take you to double your money.有一点需要注意：对于有固定收益率的投资，72法则才最好使。然而大多数的投资并没有长期固定收益率，不过你可以用平均收益率来代替，这样也能算出你的投资多久才能翻番。