Fun with FIRE Numbers

Fun with FIRE numbers

You’ve come over to the Dark Side, determined to shake off the yoke of employment. You are going to save an eyeball-popping amount, strive to make more money and to spend microscopic quantities. You plan to be creative in your side hustles and as flexible as a yogi. That brings us to the question: How will you know if you are succeeding? How do you measure your success (or lack thereof)?


You have to track them, understand them, tame them, and admire them. The path to financial independence is paved with numbers (and, of course, good intentions) of every shape and size. The sheer variety of numbers boggles the mind. Learn to love them, young Padawan, and make pretty graphs with them, and moon over them, halo shining brightly.

First, I present to you the Adult Numbers, each wearing a suit and tie, serious, some smoking cigars.

1. Net Worth (NW)

NW = Assets – Liabilities

Your assets are your bank accounts, the equity in your home, your investments, your brain (all the good stuff. If it makes you smile, and feel proud, it is an asset). Your liabilities include your debt – mortgage, credit card, student loans, and your shitty attitude (if it is giving you an ulcer, or if you’d like very much to pretend it doesn’t exist, chances are it is a liability).

Technically you should include things like the value of your car, household goods, art (no, not the pictures drawn by your toddler, hanging on the fridge) etc. in your assets. I don’t. It is too much of a hassle.

If you know your NW, you have a handle on your finances; the good, the bad and the ugly. This is an important number. Ignore it at your own peril.

For some excellent financial porn to go with your morning coffee or evening bourbon, head over to Rockstar Finance and pore over the list of blogger net worths.

2. FIRE number (aka Investment Assets)

25x your annual expenses

This is the amount of money you must squirrel away before you can flip off your manager and ride off into the sunset, guns blazing (or, you know, politely say goodbye, and drive home to your family. Whatever floats your boat). This is typically calculated as 25x your annual expenses. e.g. if you spend $40,000 a year, you’ll need to hoard 1 million dollars before you can cut the cord. When you reach your FIRE number you will have what is affectionately known as FU-money.

Why 25x? This is based on the 4% Safe Withdrawal Rate as determined by the Trinity Study. Several most excellent writers have explained the 4% rule in detail, so I’m just going to point you their way with the following advice: take the time to understand the rule, understand what you are comfortable with (3% instead of 4% maybe?), pick your FIRE number and go for it!

Why is your FIRE number not the same as your Net Worth?

Because you can’t buy a dozen eggs with the equity in your house. In other words, you can’t live off some of your assets; they don’t generate income. The numbers are related, but they aren’t the same. Your fully owned house, e.g. may help you need a smaller FIRE number, because you don’t have to take rent into account when calculating your annual expenses.

3. FIRE date

Your personal 4th of July

The date you become financially independent (i.e. size of Stash == FIRE number). You may have an RE (Retire Early) date that is completely independent of your FI (Financial Independence) date. You may choose to never RE.

My FIRE month is Jan 2021. I haven’t picked an exact date just yet. I plan for there to be celebrations and jubilations and much dancing in the street on my FIRE date.  

4. Savings Rate (SR)

SR = (Total savings / Total income) * 100

Feel free to use this image, just link to www.SeniorLiving.Org
Photo credit: www.SeniorLiving.Org

Savings rate is the rate at which you add to your stash and determines whether your FIRE date will be right around the corner or far away in the distant future when you are saggy and your tattoos are faded and wrinkly.

What exactly should you include in your total savings amount? It is pretty common to include both your taxable and non-taxable savings (i.e. contributions to retirement accounts, including employer contributions). Some people also include the principal of their mortgage paid. Other include the principal paid towards any student debt. Choose what makes sense to you.

Total income is typically your net income (post tax).  

Fire numbers are fun

OK, we’re done with the Big Important Numbers. Now let’s look at some fun ones. The journey to FIRE can get pretty boring. Once you’re saving like the proverbial ant, and making progress towards your FIRE date, there really isn’t that much more to it. You could watch the market (and attempt to not grow an ulcer in the process), or you could play with these fun numbers.

Your ‘day of the year’ number

This one is the brainchild of an enterprising user named FIGOALS on /r/financialindependence.

Imagine that your FIRE journey is a year long i.e. on Jan 1st you have $0 and on Dec 31st of that imaginary year you hit your FIRE number. What day of the year is it for you today? I’m at the end of summer, August 26th, and winter is coming.

You can have a lot of fun with this number. You could refer to your FIRE journey in terms of the seasons. You could find yourself in the previous year if you have significant debt (though that probably won’t be that much fun). You can plan a little celebration for yourself every time your number hits a U.S. holiday. What will you do for 4th of July? How about Memorial day?

Coast Number (a.k.a. your Barista number)

When your FIRE number is large enough that you could stop saving and eventually retire at the “regular” retirement age of 66. In other words you have already saved enough that you could “coast” to retirement as long as you find a job that pays your bills. Are you ready to coast just yet? I am.  

What <insert expensive commodity> are you worth today?

You are probably too sensible to own an outlandish car or an insane watch, but it can be fun to measure your NW or FIRE number in terms of expensive things. You can go from being a used Toyota Corolla with a 100,000 miles on it to a Tesla, then on to a Lamborghini, and who knows, maybe one day even a Bugatti.

Why is this fun? You get to create a bunch of intermediate milestones to watch and feel pleased as punch when you meet them. It tends to be more interesting to track than the 100k, 500k, 1 million progression.

What could you pay for if you retired today?

If you retired right now with your current savings, what would your passive income cover? Your internet bill? Your grocery bill? How about gas? Maybe you could treat yourself to a coffee every week? I enjoy playing this game and gradually watching my passive income go from being a joke to serious business.

The Every Dollar Saved Number

This one is attributed to a user named wannabe_fi on /r/financialindependence. I’ve massaged the original formula just a little.

Would you like to know how much closer to FI you get with every dollar that you currently save?

Plug this formula into Google Sheets:

=“Every $ saved buys me”&TEXT((NPER(Rate_of_return, -Annual_savings, -Current_total_savings, FIRE_number) – NPER(Rate_of_return, -Annual_savings, -Current_total_savings-1, FIRE_number))*525600, “00.00”)&” minutes of freedom”


  • Rate_of_return is your expected annual rate of return on your expenses (e.g. 0.05)
  • Annual_savings is the total amount you expect to save in a year
  • Currant_total_savings is the amount you currently have saved up
  • FIRE_number is defined above

When I plug my numbers in I get: Every $ saved buys me 03.04 minutes of freedom.

This makes it unbelievably easy to save! Every time I ask myself do I want to spend X or get 3X minutes closer to FI, guess what the answer is?

FIRE is all about the attitude, not the numbers

FIRE involves all sorts of numbers, but the whole is more than the sum of the parts. When you boil it down to its essence FIRE is a mindset, an attitude. It is a way of living. The numbers are essential, they can even be fun, but they only tell a small part of the story. Spend the time to get to know all your numbers, and to enjoy them, but remember to also enjoy this wonderful journey you are on to financial independence and early retirement. It is going to be a story you’ll be proud to tell your grandchildren.

Are you coasting? What day of the year are you? Are you a Bentley yet? Use the comments to share your fun numbers. Do you have other numbers that you have fun with?


11 thoughts on “Fun with FIRE Numbers”

  1. I heart numbers. Spreadsheets, too. In particular, I’ve enjoyed watching my own numbers look better and better since I really started to pay closer attention to them.


  2. I must admit the only spreadsheet I use is one to rebalance my portfolio with major deposits and yearly to make sure my asset allocation is on track. As for the rest of the post, well done on laying it out nice and simple for everyone to follow along and hopefully some new members of the personal finance community join in. Cheers ~ Chris

    1. Thanks Chris. I’m pleased that I managed to make the numbers seem accessible. Your feedback is appreciated.

  3. **Warning: Backhanded compliment ahead!***

    Just wanted to say that while none of this is ground-breakingly new information, I really love the way it’s presented! Brief, to the point, universally understandable, and pretty informative and motivational in a “I want to figure out where I stand, RIGHT NOW!” kind of way.

    I wanted you to know that because I think this is the kind of post that gets new people interested in FI. So, you just became the youngest blog to make my new Pinterest board for “Best FI Posts of ALL TIME” Hopefully it helps more people see this post 🙂

    1. *Blushing and accepting backhanded compliment with good grace and just the appropriate sprinkling of modesty and humility*

      Thanks for including me. It has been a while since I’ve been the youngest anything at anything : )

      1. Absolutely! Please check out my calculation of the how every dollar buys x minutes of freedom. I did my own thing there, but couldn’t tie it to the calculation you had in the blog post. Love your blog-can’t wait to see what the year brings for you!

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