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。

How to Use the Rule of 72
如何使用72法则？

If you're ready to put the Rule of 72 to work, here's what to do. To estimate how long it takes for your money to double, simply divide 72 by the interest rate. The result is how many years it will take for your money to double at that rate.
如果你打算开始使用72法则，这是你需要做的。想要简单地预测投资本金何时翻番，你只需要用72除于收益率即可。结果就是该收益率下你的本金翻番所需要的时间。

For example, let's assume you can earn a 6% rate of return. How long will it take $1,000 to grow into $2,000? Here's the equation:
举个例子，比如投资回报率是6%，需要多长时间1000美元的本金才能变成2000美元呢，等式在此：

72 / 6 = 12 years
72 / 6 = 12 年

In this example, if you invested $1,000 into an account that earned a flat 6% annual rate of return, after 12 years, your investment would be worth around $2,000.
在这个例子中，你投资1000美元，固定收益率是6%，在12年后，你将拥有2000美元。

That's a simple way to calculate earnings but it can be powerful for determining whether there's a gap or potential shortfall in your savings strategy. The Rule of 72 can help you gauge whether your current savings plan is sufficient for reaching your short- and/or long-term goals.
虽然72法则只是一个简单计算投资收益的方法，但它更大的价值是计算出同一笔钱用来投资和用于储蓄之间的利差是多少。72法则能帮你判定你当前的储蓄计划能否达到你的短期或长期目标。

The Rule of 72 by Interest Rate
收益率72法则

Since interest rates can vary, the Rule of 72 calculation can produce different results, based on what you've invested in. To save you a little time, here are some common interest rates, plus the amount of time it will take for you to double your investment with each interest rate:
虽然收益率各有不同，但72法则能根据收益率得出不同的结果。为了节省你的时间，这里是常用的收益率和对应的本金翻番所需时间。

1% - 72 years
1% - 72年

2% - 36 years
2% - 36年

3% - 24 years
3% - 24年

4% - 18 years
4% - 18年

5% - 14 years
5% - 14年

6% - 12 years
6% - 12年

7% - 10.3 years
7% - 10.3年

8% - 9.0 years
8% - 9.0年

9% - 8.0 years
9% - 8.0年

10% - 7.2 years
10% - 7.2年

11% - 6.5 years
11% - 6.5年

12% - 6.0 years
12% - 6.0年

Remember, It's Just an Estimate
记住，它只是一个估计

Keep in mind that this is just a quick estimate. Depending on changes in the rate of return over time, what you're invested in, how you invest it, how interest is applied, and possible tax implications, the actual amount of time needed to double your money will vary.
记住，这只是一个快速估计。收益率、本金数量、投资方式、计息方式、税务影响，这些因素都会影响72法则得出的结果。

Even so, the rule of 72 can be helpful when you quickly want to compare the rate of growth of two investments. You can easily see at a glance which one is likely to yield a better rate of return to decide where the best place is to allocate your money.
虽然如此，当你想快速比较两笔投资时，72法则还是很有效。你可以一眼看出哪笔投资的收益最好，这样你可以决定如何配置你的钱。

The rule of 72 also works in reverse — it can be helpful in understanding the power of inflation. If you consider the average long-term rate of inflation is between 3% and 4%, you'll notice when you use the rule of 72 that something worth $100 today will cost $200 in about 20 years.
72法则也有别的用法，它可以让你很好理解通货膨胀的力量。如果长期通货膨胀率在3%到4%之间，使用72法则后，你就会发现，现在价值100美元的东西在20年后需要200美元去购买。

This can help illustrate the power of inflation, which can have a significant impact on your retirement strategy. And, the Rule of 72 is also useful in realizing a rate of return over time that can not only overcome inflation, but also taxes, which can take a bite out of your investments and retirement income.
这可以说明通货膨胀的重要性，它会对你的退休计划有重大影响。还有，通货膨胀和税收能大程度稀释你的投资本金和退休收入，而72法则能帮你找到那个能战胜通货膨胀和税收的投资回报率。