Coast FI(RE) Explained – The Most Powerful Financial Independence Milestone

Coast FIRE is becoming more popular as a Financial Independence strategy all the time. Coast FI is a very powerful concept. Our own approach to FIRE is based around Coast FI principles and has allowed us to claim our freedom back and semi-retire in 2020. We are now coasting to Financial Independence. In this article, I’ll share the ins and outs of this strategy. I’ll also show you how you can calculate your Coast FI number and share our free Semi-Retirement and Coast FI calculator.

What is Coast FI?

Coast FI is the point at which you have saved enough to get to FI by the time you reach the traditional retirement age without having to make any further contributions to your portfolio. Once you reach this point you can stop saving altogether. As long as you don’t touch your nest egg, it will generate enough income in retirement – thanks to the magic of compound interest.

I have spent a lot of time considering the different milestones on the path to FIRE. To me, that Coast FI is a really important one that deserves a lot more attention than it has been getting. Once you reach Coast FI, you don’t have to save another dollar and you will still be ok later on. From that point on you only need to earn enough to cover your monthly expenses. How good is that?

I believe that Coast FI is possibly the most important milestone on the way to Financial Independence. Why? Just think about how many 50 or 60 somethings worry about not having enough money in retirement. Once you get to Coast FI, that is one thing you don’t ever have to be concerned about. 

How to calculate your Coast FI number

Calculating your Coast FI number is a bit more complicated than figuring out your numbers for other FI milestones where you simply have to multiply your annual spending by a specific number (Flamingo FI: 12.5x, traditional FIRE 25x). The reason for this is that your current age is the most important factor for Coast FI. The younger you are, the lower your Coast FI number.

Note: If you are not a math person you can go straight to the next paragraph and use the calculator to figure out your Coast FI number!

This is the formula to calculate your Coast FI number:
Coast FI number = FI number * (1 + Interest Rate) ^ -Number of Years to Retirement

Here is an example:
John is 45 now and wants to retire at 65 – 20 years from now. His FI number (25x annual retirement expenses) is $1,000,000. He thinks his investments will grow by 7% after inflation per year.

John’s Coast FI number = $1,000,000 * (1 + 0.07) ^ -20 = $258,419

So John could stop saving straight away, get a part-time job in a café (this is why Coast FI is mistakenly called Barista FI sometimes) and still enjoy a comfortable retirement once he turns 60.

One thing to remember about your Coast FI number is that it is not static, it is a moving target. This is because your Coast FI number will be higher the closer you get to retirement.

Flamingo FI requires a bigger nest egg for most people than Coast FI. The only exception is people who are less than 10 years away from traditional retirement. In this case, your Flamingo FI number would actually be lower than your Coast FI number.

The Semi-Retirement and Coast FI Calculator

If the formula above makes your head spin, I have a treat for you: The Money Flamingo Semi-Retirement Calculator! With our free calculator, you can calculate your Coast FI number and age. It also calculates your Flamingo FI and Traditional FIRE numbers and the age at which you could reach these FIRE milestones. If you think semi-retirement might be an option for you, this is a great way to get a realistic idea of when you might be able to exit the FIRE highway. To download the calculator you can either head over to the Semi-Retirement Calculator page where you can find more information about how to use it and what the results mean. Alternatively, you can enter your details below to download the calculator straight away.

Coast FI vs Flamingo FI

I often get asked what the difference between Coast FI and Flamingo FI is. Flamingo FI could be described as a variation of Coast FI. With Flamingo FI, you will reach FIRE after 10 years (if your investments generate inflation-adjusted returns of 7%). For most people, this will be a lot sooner than if they go the Coast FI route.

With Flamingo FI, there are three retirement phases – semi-retirement (10 years if everything goes to plan), FIRE and Traditional Retirement. With Coast FI, there are only two – a long phase of semi-retirement and traditional retirement.

Both Coast FI and Flamingo FI are milestones on the way to full FIRE. At the same time, both are potential exits on the road to FIRE that you can take if you can’t or don’t want to soldier on in a full-time career until you hit your magic number. Exiting at Coast FI or Flamingo FI is like getting off the highway and taking a leafy country road to get to your destination at a slower, more relaxed pace.

In the case of Coast FI, you stay on the country road until you reach the standard retirement age. In the case of Flamingo FI, you should get to your destination after about 10 years. The alternative is to stay on the highway and race to FIRE – it’s all up to you. What I want to stress is that there are many roads that lead to FIRE, and everyone should make a conscious decision about which road is the right one for them and their family.

Here is a graphical comparison of Coast FI, Flamingo FI, and traditional FIRE for someone in their 30s:

We would like to reach FIRE (and be able to stop working completely if that’s what we feel like doing) before the traditional retirement age. That’s why Flamingo FI is a better exit strategy for us. We are now officially semi-retired and loving it. Everyone is different though and Coast FI certainly is a great option for many people.

Who should consider Coast FI?

We will all pass the Coast FI at some stage on our path to FIRE. But who should consider using Coast FI as an exit? Anyone who is not happy in their job. Professionals close to burning out. People who want to prioritise spending time with their kids. I believe that everyone should at least consider Coast FI as an option. It is a great choice for anyone who, for whatever reason, wants to or needs to stop working full-time or cannot continue saving for retirement (and FIRE).

What do you think about this concept? Is Coast FI something you would consider?

17 thoughts on “Coast FI(RE) Explained – The Most Powerful Financial Independence Milestone”

  1. This is very motivational to see that we have so many options on our way to FIRE. Personally I like the the Flaningo FI option compared to the Coast FI option, for the fact that I have saved up more of a security buffer in case things in the market go pear shaped. Love the Coast FI icon by the way in the graph!

  2. Hi MF, long time lurker on your blog, love your content. I am seriously considering coastFI for myself. I was made redundant a few months ago. Plus I am struggling with some semi permanent health issues that get worse when I am stressed. Don’t know how much longer I can / want to keep hustling for FIRE and would also be ok with working part time. I’m 43 with a decent nest egg but nowhere near FIRE. Past my coast fi number however!

    • Hi Firebum,
      Thanks for your comment! Sorry to hear you aren’t doing too well at the moment. Congratulations on reaching Coast FI! I don’t know your full story but it sounds like you could definitely downshift a little and enjoy the perks Coast FI has to offer.

  3. So that’s what it’s called! Been ‘Coasting’ (on the Coast) for 10 years now… still love my job but also love spending time with my 2 kids and all the other things that define a balanced life. Knowing I only need to work enough to pay the day-to-day bills (and that life beyond 60 is taken care of) is very liberating; and who knows… I might not stop then either.

  4. Thanks for commenting Burrow! Your lifestyle sounds fantastic. Would you mind elaborating a little on your story? I’m sure a lot of readers (Mr. Flamingo and I included) would love to hear more about how you are coasting on the coast!

    P.S.: I’m glad you finally have found out what your lifestyle is called! 😉

    • I got lucky! I earned a decent income straight out of uni and learned the principles of (what was later to become) FIRE in those early years. Being naturally frugal, I had a high savings rate and invested it all in growth assets – in and out of super. Time (and healthy returns) has done the rest.

      The interesting thing is that I was always keen to RE. But as I drew closer to FI, my life gained more balance and the desire to retire slipped away. Instead, I now work part-time, earn enough to cover day-to-day expenses and know my future is taken care of.

  5. Brilliant post, very liberating to see how many variations of financial independence are available than just a hard and fast FIRE (25 x) metric.

    Personally, I’m aiming for under 10 years so the Flamingo FI number is lower than the Coast FI number!

    Keep it up.

    • Thanks Fire Park! There is a whole universe of options outside that metric and I think lots of people get discouraged because they think standard FIRE is the only way. We use more conservative growth assumptions for our Coast FI calculations, so our Coast FI number is also really close to our Flamingo FI number.

      • Does coast fire money have to be outside of Super? If in and out of Super does count we are almost there! That would be a relief as with 4 kids I would love to know we are on track! No doubt there are some things ahead that’ll knock us off course! Having said that neither me or my husband have worked full time since a brief stint in 2017! Our house is almost paid off (regional Vic!). In our mid 30s I feel we are doing ok… reading FIRE stories makes me think we’ve done it all wrong…yet it usually feels in good balance! Having said that our eldest kid is almost a teen and the youngest is not yet one, fair to say over a decade ago we decided raising awesome people is our real job!

  6. Hi Money Flamingo,

    I’ve started reading your blog after it was recommended by the Spaceship app and been loving it so far!

    Flamingo FIRE resonates with me because like you said, it allows you to work a job you enjoy sooner than traditional FIRE, and it’s a smoother transition out of regular work.

    I love the graphical comparisons of Coast vs Flamingo vs traditional – with flamingo, should there be two flamingos worth of time before I come drops to zero, to reflect that you get to full FI faster than Coast, yet slower than traditional?


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