Want to retire early? This app tells you how long it will take.

At a high level, step one is to figure out how much you need to save and step two is to figure out how long it'll take to reach that amount of savings.

Safe Withdrawal Rate

I'd like to introduce a term: the Safe Withdrawal Rate (SWR). Suppose you have a $1M nest egg. A SWR of 4% would mean that if you withdrew 4% of your nest egg each year — $40k — it'd last forever. The interest it generates would offset the money you take out.

That begs the question of what the SWR is. The short answer to that question is 4%.

Here is a longer answer to that question. In 1998 there was a paper by three professors of finance at Trinity University. This paper is known as the Trinity Study. They asked the question: if you retired in 1926, what would the SWR be? What about 1927? 1928? 1929? So on and so forth up until 1981. The answers depend on things like stock market performance and inflation, but have always ranged from 4-8.5%.

Trinity study results

What would you like to use for your withdrawal rate? Think about how aggressive or conservative you want to be. 4% is conservative, 7% is aggressive.


Nest Egg

Now that we have your withdrawal rate we're quite close to figuring out how big of a nest egg you need. We'll approach it with the following two questions:

  1. How much do you spend per month? Think: rent, groceries, etc.
  2. How much do you spend on top of that every year? Think: vacations, medical, miscellaneous, etc.

To be clear, the question at hand is how much you're planning on spending once you're retired, not what you're spending right now. You might spend less during retirement because eg. you have more time to cook. Or you might spend more because you want to indulge in travel and hobbies.

With the three parameters we've entered in so far, we can compute two useful results:

Total yearly spending
Retirement target (nest egg)

If you're extra conservative, you may want to add a little buffer to your retirement target. Ie. maybe you want to add an extra $50k to the previous result to provide additional breathing rooom. You can do so below.

Years Until Retirement

Cool. We know that you are targeting a $875,000 nest egg. The question now becomes: how long will it take to get there?

In the spirit of keeping things simple and accepting results that are in the right ballpark, let's take an easy approach to answering this question.

How much do you currently have saved up?

Awesome. That means that you need $575,000 more to retire.

Now, how much do you think you can save each year?

And how much interest do you expect it to generate each year?


With these three values we can now get our final answer of...

Years until retirement

Condensed page

Congratulations, you made it through!

At this point you probably want to play around with the numbers some more. For that, I'd recommend heading over to the condensed page. It's easier to play around with the numbers on that page. It also has a cool feature where you could compare stuff to a baseline and set a new baseline. Check it out.

Wrapping Up

I hope you enjoyed using this tool. If you did it'd be great if you shared it with your friends. If you're interested in early retirement I'd recommend Mr. Money Mustache. If you have any questions or comments, shoot me an email. You can also buy me a coffee or check out the code on GitHub.

Cheers! 👋