How To Calculate Your Financial Independence Number

Financial independence number

If you are pursuing financial independence and early retirement, you should have a financial independence number. If you have been on an FI journey for a while, this is nothing new to you.

The financial independence number is the amount of money you need to be able to live off the returns on your net worth without depleting your net worth. Once you have money in the bank equivalent to your financial independence number, you can call yourself financially independent for life because it does not deplete your net worth.

Before we get to how you calculate your financial independence number, we need to understand a few things first.

How much money will you spend?

Before we dive into the calculations, you need to find out how much money you will spend each month once you reach financial independence.

A good starting point is to find out how much money you spend per month at the moment. If you don’t have a budget where this is visible, try to give an estimate of how much money you spend every month everything included (e.g. housing, transport, clothes etc.).

Keep in mind that some costs go up once you achieve financial independence and perhaps retire early.

Multiply your monthly spending by 12 to find out what your required yearly spending is when you become financially independent.

As an example, I spend roughly $2,500 per month, which makes my yearly spending requirement $30,000.

What is your safe withdrawal rate?

Next up is your safe withdrawal rate. This is used in combination with your yearly spending to calculate your financial independence number.

Much has been written about the safe withdrawal rate. People usually don’t disagree with the concept of safe withdrawal rates, but they like to discuss the value that it should have.

The safe withdrawal rate is the percentage of your net worth that you can withdraw each year without running out of money before you die. It originates from a 1998 study called the Trinity study. This is where the 4%-rule comes from if you have ever heard about that.

The Trinity study argued that you should have a safe withdrawal rate of 4% by looking at returns from 1925 to 1995. In that time period, it would have been highly unlikely that you would have depleted your net worth if you had only withdrawn 4% every year. This is assuming that your net worth would still have been invested in a stock-dominated portfolio.

I personally use a 4% safe withdrawal rate, but others argue that you should be even more conservative such as using a 3% safe withdrawal rate.

Why do I use 4% then? Well, if it turns out that 4% withdrawal depletes my net worth, I will be fine with spending less or earning some more money for a while. Keep in mind that the safe withdrawal rate assumes that you don’t make any additional income apart from investment returns.

Which safe withdrawal rate should you use? I would suggest something between 3-4%, and you’ll be fine.

Calculating your financial independence number

Now to the grand finale! Using the two financial ingredients from this post, you’ll be able to calculate your financial independence number.

You can calculate your FI number using this equation:

Financial independence number = Yearly spending / Safe withdrawal rate

As an example, my financial independence number is:

$750,000 = $30,000 / 4%

My financial independence number is $750,000. Once I have a net worth of that, I am financially independent and I can stop working for the rest of my life. Easy as that!

Having a number makes financial independence much more tangible for most people. For me it is a great motivation to have a clear goal, and I religiously track my progress every month.

If you are curious, you can also use your savings rate to calculate time to retirement using my financial independence calculator.

Your turn: What is your financial independence number?

10 comments

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10 comments

Emil February 24, 2019 - 21:29

Do you/should you adjust savings goal and withdrawal for inflation? What’s your take? Thanks for good content!

Reply
Carl Jensen February 25, 2019 - 13:52

Hi Emil,

Good question! Actually, the 4% rule is inflation-adjusted, so no need to factor that in.

You could argue that in the future when you calculate your yearly expenses it will be higher. In that case, you could update your expected annual expenses each year and calculate a new number, but it will not vary by a lot.

My general suggestion is to use the number as a guidance and not as the truth. So many things can happen before and after reaching FI, so having a goal is good, but don’t spend too much and updating it each year would be more than sufficient. Trying to predict future inflation rates and making big models will most likely make you precisely wrong than approximately right. The most important part is saving and investing as much as possible, then FI will come around soon enough 🙂

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Luke Wolmer February 13, 2019 - 17:48

Carl — thanks for this straightforward and simple explanation on how to find your FI number. I think people often get very caught up in this calculation and try to predict how their life and expenses will change in the future. At the end of the day life is unpredictable. So while calculating your FI number is important (from a goal perspective), we should not try to predict every twist and turn that life will have in store for us. Its extremely likely that the FI number we calculate today will not be our true FI number anyway, so no need to stress over the minute details of this calculation.

I noticed that in your About Me page you state you predict that you will be financially independent in 6 years. I understand you can take your current annual savings and FI number and reverse engineer the expected time to financial independence. But I am curious how you factor in salary increases, new/potential sources of income in future, etc. Do you have a master spreadsheet where you forecast your income and income sources? Or do you have a simple calculation or assumption (ex: annual savings will increase by 5% each year)?

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Carl Jensen February 14, 2019 - 21:57

Hi Luke,

Thanks a lot for a great quesiton. I highly agree with the first part of your comment. It is impossible to calculate as income and expenses both pre and post retirement are impossible to predict, so your FI number should just a guidance to be used.

I use two different FI numbers (traditional and optimistic). Normally, I would say you should just use your current salary and forget about future salary increases (it’s uncertain if/when they will come – and you might as well be fired and have no salary at all). If you then manage to get to a higher salary level, you should just recalculate your time to FI and you’ll have cut off some time until you are FI. Could you forecast your expected salary and calculate your time to retirement that way? Yes, you definitely could, but you risk being ‘precisely wrong’ instead of ‘approximately right’ as you are in the simple example.

In my optimistic case, I calculate my FI number including expected post-retirement income and expenses. Using this FI number, you can reverse engineer how long time there will be until you can retire with your current savings rate and expected returns.

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Mrs Smelling Freedom February 26, 2018 - 16:18

Hi Carl 🙂
My one concern when calculating an FI number is the fact that costs change as life changes. Factors such as children, illness or any other life change can increase your annual costs dramatically. In my case, for example, with three kids, costs have gone up through the roof 🙂 just feeding them costs a fortune lol! So the one addition I would make to your post is life stage modelling. Try to forecast your costs in your 30s, 40s, etc. Then your FI number would be 25 times the highest cost you have modelled. I’m a bit conservative so perhaps you might disagree, but the way I see it better safe than sorry 🙂

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Carl @ MoneyMow February 27, 2018 - 23:21

I agree with you, MSF! 🙂

I believe the FI number should only be used as a guideline for the kind of net worth you should aim for. As a general rule, the assumptions behind the number should of course be set according to how risk averse/seeking you are.

I agree that it is hard to predict future costs because of the many unknowns of life. Therefore, I believe that you should update your FI number at least annually because your situation changes as you go through life. I would find it hard to forecast my annual costs in 10-20 years, so I think the financial independence number should rather be seen as a dynamic number that will keep you on the right track rather than a static number that remains the same forever. I guess with the financial independence number I prefer being “approximately right” instead of “exactly wrong”. Does that make sense? 🙂

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Frinans February 14, 2018 - 10:50

Hi Carl,

As I recall, the Trinity study relies on a 50/50 split between stocks and bonds and a 0% tax on returns. Correct me if I’m wrong. So basically I have two questions.
1. How do you incorporate taxes in your calculations?
2. If you calculate based on net worth how does that compare to the 4% rule? Her I am especially thinking of including a pension in the net worth which one can’t get access to early and the value of a home which also cannot be liquidated easily.

Thx

/Sune

Reply
Carl @ MoneyMow February 14, 2018 - 11:56

Hi Sune,

You are absolutely right. The Trinity study has its flaws, and the bond/stock split and tax returns are some of them. I have read some critique of the 4% rule – one of my favorite posts is from Early Retirement Now that go through many of those points and end up with the suggestion of using a lower safe withdrawal rate than 4%, but not by a lot. They also do simulations with 100% stocks, and here the 4% actually does relatively well with 89-97% success rate depending on the time horizon of the retirement.

To answer your questions:

1. I don’t include taxes explicitly even though it would be more correct to do so. However, the negative tax effect might be offset by the (hopefully) higher returns of a full stock portfolio compared to the 50/50 split. There are many technicalities that you could tweak, but the 4% rule is for me just a guidance that is easy to communicate and aim for. In reality, you would need to make your own more precise calculations as you get closer to early retirement (for example, the 4% rule also assumes that you never work or have an income again, which I definitely will post-retirement). I am using my calculator on this site to calculate the exact time to retirement (which includes taxes, inflation etc.), but it is also just a guidance.

2. Good question. Pensions in Denmark will be accessible at the age of 60-something and hopefully you can sustain yourself on the other parts of your net worth until then, but of course, it is something to keep in mind. Again, you would need more precise calculations as you get closer to early retirement and know how your life looks then. Home equity isn’t liquid and there’s much debate about whether to include it or not. In my case, I believe it can be liquidated relatively easily (it’s a central Copenhagen apartment – crossing fingers the market don’t crash too hard) if we need the money, since we can just sell it and rent instead, which we actually plan on doing later in life.
In general, I don’t really think that much about whether I’m getting it exactly right with the 4% rule (of thumb). I believe there are arguments for (e.g. higher returns than the 50/50 split) and against (the arguments you mention). For now, I use it as a guiding principle and as I get closer to the 4.500.000 DKK, I will have to make more precise calculations – of course taking into consideration how my net worth is distributed across cash, stocks, peer-to-peer lending, cryptocurrencies, home equity, pension etc.

Thanks a lot for the great questions – it is always good to be challenged on some core assumptions in key FIRE principles that most people (including myself) tend to ignore.

/Carl

Reply
Omar April 23, 2018 - 22:05

Hi Carl !
I was gong to ask you about this very topic ! (your answer #2).
Regarding the home equity, I think we agree. I’m just buying an appartment which is quite well located, so, it should be reasonably easy to sell when needed (meaning, I will include it on the FI number). Regarding the pension, here in Belgium you can have that money not before than… (please take a seat…) 67 years, as I can’t touch a cent of that money before, I really think I should not include that money on the FI number. What do you think?

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Carl April 25, 2018 - 22:30

I very much agree with you 🙂 Pension is illiquid, so it should not be part of your net worth counting towards your FI number (In Denmark, they are thinking about increasing it to 73 years!). Generally, I don’t necessarily believe you should strictly follow the FI number, but it is a good guidance. An example is that if you expect to earn a bit of money post-retirement, then you should lower your expected post-retirement expenses with that number and re-calculate your FI number.

Reply

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