Firecalc Review: Using the Past to Predict the Future

Do you have dreams of retiring early and living life on your own terms?  I know I do- I’ve written about it before. Figuring out how to get there can be tricky. That’s why tools like Firecalc are so great.

Firecalc is a free early retirement calculator. It examines the history of the stock market, and provides data on different retirement starting points.

Firecalc was built and operates around one very simple principle:

“If your retirement strategy would have withstood the worst ravages of inflation, the Great Depression, and every other financial calamity the US has seen since 1871, then it is likely to withstand whatever might happen between now and the day you no longer have any need for your retirement funds.”

firecalc review


Of course, it’s impossible to predict what the market will do in the future. However, Firecalc believes that by studying the past performances, people can make reasonable assumptions about their financial needs in FIRE.

How It Works

First, the calculator starts with your total nest egg and withdraws the annual amount you want to live on.

Second, it figures out what would have happened to the rest of your nest egg throughout that year. Here’s where the market ups and downs come in, as well as interest, dividends and fees.

Thirdly, Firecalc creates a compounding and predictive cycle for your retirement scenario. It takes these results and applies them to the following year, and so on until the end of your predicted timeframe. You can see what the market would have done to your money, and how it would have held up over time.

From this information, a chart is created showing all the results of your portfolio. The calculator does this again and again, starting in 1872. It formulates a retirement plan starting in each year thereafter. You now have data on how your nest egg funds would hold up if you retired in each year since 1872.

Finally, Firecalc gives you a percentage on how often your retirement plan would have worked out for you.

Firecalc is interested in showing it’s users a picture of what happens as you withdraw money in an ever changing market. When markets are up, you can withdraw at your same rate and know that you’re leaving enough that it will grow. But taking money out of your portfolio “when the market is down depletess the future earning power of the portfolio, potentially to the point where it cannot recover.”

This is a HUGE THING for those interested in FIRE. The ultimate question for people who want to retire early is ‘How do I ensure I don’t run out of money?’ This calculator provides insight into how safe (or unsafe) your early retirement plan is, based on how it would have withstood every market condition that’s existed.

The website also provides a Resources page, so you can read their suggested books, or play around with a tax planning tool for early retirees. You can also donate to keep the calculator running, as it is only a labor of love and not a business.


The website is pretty old school. It’s not super user-friendly, and it’s not pretty to look at. The information it does calculate is pretty invaluable. But, it’s hard to get everything plugged in due to the difficulty of using the site.

If you’re really committed to FIRE, this is worth playing around with. If you’re mildly interested, there are other places to start your FIRE research. I give this a 3.5/5 stars.

Looking for more great articles on how I handle my money? Try these articles:

Why I Have Trouble Spending Money

How to Save for Vacation

How I’m Paying Off That $1,200 Credit Card Bill



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