Coast FIRE Calculator 2025

This page will introduce the features of the Coast FIRE calculator (or someone say it as coastfire calculator), the underlying calculation method, and what this concept means for us. Coast FIRE is when your retirement accounts have enough funds that no additional contributions are needed; the growth of your existing assets will be sufficient to cover your living expenses by the time you reach traditional retirement age.

Once you’ve reached Coast FIRE, you no longer need to keep saving and can instead focus on maximising your current spending.

Coasting to FI

Coast FIRE (or CostFIRE) refers to a financial strategy where you save a lump sum in the short term, let that money grow on its own over time, and then continue working at a job you enjoy just to cover your daily expenses. In other words, you live frugally for a few years, save up a solid amount, and then you can become a relaxed and happy “living paycheck-to-paycheck” person — by choice, not necessity.

Two Examples

Let me give two examples to explain how it works.

I’m 30 years old, earning less than $2,800 USD a month, with modest savings—low six figures in USD. I know I’ll likely face a midlife crisis, become less competitive, and see my income decline. I want to retire at 50, but I won’t be eligible for a pension until 63.

So I need to save a certain amount for my retirement at 50—let’s say $1 million USD. That works out to about $5,000–6,000 USD per month in expenses. With that sum, even if I hit hard times in middle age, I won’t be in a tough spot. And with pension income later, I should be fine.

But I don’t want to be a slave to that $1M goal. I don’t want to sacrifice everything—maximising income and minimising spending—for years on end. I know I don’t have the willpower for that.

The idea behind traditional FIRE is to save that $1M and then retire. But Coast FIRE is more relaxed. With smart planning, I don’t need to go to extremes—I can rely on time and compound interest to help me reach the same goal.

Back to the example: To retire at 50 and cover $5,000/month (or $60,000/year), I only need to save about $500,000 USD now, and I can spread that over 10 years. That’s $5,000 USD/year or about $400 USD/month—a manageable amount that doesn’t drastically affect my lifestyle.

Another example

If we use the S&P 500’s historical average annual return of 10.5%, a young couple, both 25, earning $80,000 USD after tax per year, can pursue Coast FIRE by saving 60% of their income ($4,000 USD/month). If they plan to retire early at 55 with $1 million USD in savings, they only need to live frugally for 39 months. After that, they can switch to a relaxed, paycheck-to-paycheck lifestyle at age 28.

If they save 70% of their income instead, they only need 33 months. And if they have an employer-matched retirement plan, their nest egg would be even bigger. Or if they decide to retire like the average person at 65, their investments would grow to $2.78 million USD.

Of course, life happens, and every stage brings new plans. Even after saving that money, they might face pressures like buying a house or raising kids. So it’s not like you can completely relax after hitting that number. And for many people, $1M doesn’t even feel like enough to retire. But in countries like Canada, the U.S., or Australia, many retirees only have a few hundred thousand in assets.

In the end, the Coast FIRE lifestyle gives us more choices, and for many ordinary people, it provides a sense of confidence and security about the future.

Using Coast FIRE calculator

This Coast FI calculator (or CoastFI calculator) is part of Financial Independence Calculators. This interactive calculator makes it easy to visually track the growth of your assets.

One line shows the amount of money you would need at each age to naturally grow into your target retirement amount by your chosen retirement age. The other line represents your actual asset growth over time.

When your actual assets surpass the required growth line, you’ve reached Coast FIRE—meaning you’ve saved enough that, from this point on, you no longer need to save more. Your current assets will grow on their own to cover your living expenses at retirement.

The math of Coast FIRE Calculator

This calculator is built on the standard FIRE calculator, with one additional step included. This is how to calculate your FIRE number:

The formula to calculate your FIRE number using the Safe Withdrawal Rate (SWR) is:

\[ \text{FIRE Number} = \frac{\text{Annual Spending}}{\text{SWR}} \]

For example, if your annual spending is $40,000 and the SWR is 4% (i.e., 0.04), then:

\[ \text{FIRE Number} = \frac{40,000}{0.04} = 1,000,000 \]

You need

• At the beginning, you need to enter your current age, current annual income, and annual expenses.
• You should also input your current total assets, along with the allocation of these assets across different investment types (the total should add up to 100%). Different investment types will have different rates of return.
• You may enter decimal values if you believe they provide a more accurate estimate.
• The investment return rate is an estimate of how your invested money grows annually. This calculator will provide a default value for your convenience, but you can update it for a more precise estimate. Based on the past 10 years of S&P 500 returns, this rate is typically above 7%.
• The inflation rate reflects how your cash loses value over time. This is usually around 3%, though the number can vary depending on the country.
• The Safe Withdrawal Rate (SWR) estimates the percentage of your assets you can withdraw each year for daily expenses. This is typically set at 4%. The lower this rate, the harder it is to achieve FIRE (Financial Independence, Retire Early), as it means you need a higher total amount of assets.

Step by Step Calculation

This is how to calculate your net worth for next year:

The formula to calculate your end-of-year savings is:

\[ \text{End of Year Savings} = \text{Previous Savings} \times (1 + \text{Growth Rate}) + \text{Annual Savings} \]

This equation assumes your previous savings grow at a certain rate, and you add new savings at the end of the year.

Compound interest calculation is one of the core components of the entire calculator.

The standard compound interest formula is:

\[ A = P \times (1 + r)^t \]

Where:

• A = the future value of the investment or loan, including interest
• P = the principal amount (initial investment)
• r = the annual interest rate (as a decimal)
• t = the number of years the money is invested or borrowed for

Then, the method to calculate your Coast FIRE number is as follows.

The formula to calculate your Coast FIRE number is:

\[ \text{Coast FIRE Number} = \frac{\text{Annual Spending}}{\text{SWR} \times (1 + n)^t} \]

Where:

• Annual Spending = the amount of money you plan to spend per year in retirement
• SWR = Safe Withdrawal Rate (as a decimal, e.g. 0.04 for 4%)
• n = expected annual growth rate of your investments (as a decimal)
• t = number of years until retirement

Inflation consideration

Inflation is a crucial factor to consider when planning for retirement. Unlike stocks and mutual funds, cash gradually loses value over time due to inflation. The inflation rate typically ranges from 2% to 3%. This calculator already takes inflation into account—you just need to adjust the specific parameter. If you have a more pessimistic outlook, you can set a higher inflation rate.

Coast FIRE vs. Traditional FIRE

In my opinion, the biggest difference between Coast FIRE and Traditional FIRE is that Coast FIRE provides a good work-life balance, which allows me to have less financial pressure. Furthermore, by using this calculator, I can know my life’s financial plan in advance, so I have a clear picture in my mind.

Coast FIRE vs Barista FIRE

Coast FIRE and Barista FIRE share many similarities. For example, both require working now and for some time, then transitioning to a lower-paying job for several years before achieving FIRE status and early retirement. People sometimes confused about these two type of FIRE, the Coast FIRE and Barista FIRE. Based on my understanding, they have these differ parts:

• Barista FIRE require you continue your work but lower income which is lower pressure.
• Coast FIRE means you have saved enough money but still keen to work, you enjoy working so you can choose the job you do like, not for money only.
• Coast FIRE allows you to stop contributing to your FIRE account and simply rely on the income generated from your accumulated assets to naturally glide toward FIRE. All you need to do is earn enough to cover daily expenses without saving extra.
• Barista FIRE is a middle ground where, after achieving financial independence, you choose part-time or non-full-time work to cover living expenses while still enjoying a retirement lifestyle. This means you can stop adding to your FIRE account and even withdraw some funds for daily use, supplementing any shortfall with a part-time job (like being a barista), which is where the name comes from.

I have created an online Barista FIRE calculator as well.

Key Components of Coast FIRE Planning

Achieving your Coast FIRE target depends on several key factors, with the most critical being your planned annual expenses after retirement. By testing different numbers, you can clearly see how the results change, and it becomes apparent that this variable has the greatest influence. Things like investment returns and inflation are generally uncontrollable, while your current net worth is a fixed starting point that cannot be immediately altered.

Trade-Offs of a Slower Path to Coast FI

The Benefits of Coast FIRE

Coast FIRE offers some great benefits. It encourages you to plan for retirement well in advance and provides a long-term perspective on creating a healthy work-life balance. This approach opens up possibilities for more flexible career options, reduces general life anxiety, and allows you to leverage the power of compound interest for steady asset growth. The end goal is to cultivate a higher quality of life.

I like my current job because the hours are relatively flexible. On the condition that we don’t upset our family’s budget, my spouse and I can take turns cutting back on work, which gives us an early taste of the FIRE lifestyle.

Once our kids are in university, we plan to switch to a lower-spending mode. The goal is to reach a net worth of at least 25 times our annual expenses and then continue to work (essentially Coast FIRE or semi-retirement).

Compared to complete retirement, I much prefer having something to do. The key difference is that without financial pressure, your whole mindset changes.

Another factor to consider is job mobility. If we move to another city in the future, will I still have the ability to earn money? My current job is good, but it has regional and resource limitations, so it would be best to develop a professional skill that would allow me to relocate easily.

The Challenges of Coast FIRE

However, Coast FIRE comes with some significant disadvantages. It extends the timeline to your full retirement since you are no longer actively accumulating wealth at the same pace. Furthermore, markets are volatile; a significant downturn could interrupt your investment returns, impacting the growth of your wealth and affecting your overall retirement plan. Life plans also change—your goals will differ at various stages. For instance, you might have children in your 40s, which would dramatically change your family’s expenses. Lastly, Coast FIRE demands a high level of self-discipline, which is honestly a difficult trait to maintain consistently over many years.

Coast FIRE Examples

Fiona told me,

Our financial strategy in Canada and the US is diversified across several channels. For our children’s education, we max out monthly contributions to their Registered Education Savings Plans (RESPs). We also ensure both of our Tax-Free Savings Accounts (TFSAs) are fully funded, consistently investing in an S&P 500 index fund. Additionally, we hold a mix of term and participating life insurance policies to cover all family debts. However, the cornerstone of our portfolio, and the asset class I’m most optimistic about, is real estate due to the power of leverage.

Our overarching approach is to buy and hold, and since it’s a long-term plan, we aren’t overly concerned about liquidity as long as our family’s cash flow remains positive and insurance covers unforeseen risks. A significant advantage of real estate is that over time, mortgage debt decreases while rental income rises, allowing us to eventually enjoy the dual benefits of both capital appreciation and positive cash flow. We also view the taxes we pay annually as a way to indirectly build our borrowing capacity, effectively converting expenses into future investment opportunities. Even with today’s high housing prices, we believe there are still opportunities. It’s clear we’re late to the game; friends who began investing in property a few years ago are now, at least mentally, able to completely relax.

How to achieve Coast FIRE

The essence of the Coast FIRE strategy is to build an investment fund early on and then let it grow autonomously, eventually leveraging the power of compounding to finance a very low-stress retirement. This is why securing that initial capital as early as possible is crucial. During the initial phase, the focus should be on aggressive saving or taking on extra work to maximize your contributions. It’s also vital to conduct regular financial check-ups and make adjustments along the way, ensuring that your plan remains in sync with reality.

Next Steps

Everyone’s Coast FIRE goal is unique because each person’s spending, savings, and career are different. For this reason, someone else’s plan isn’t necessarily better; you should confidently follow your own path. Regularly checking in on your financial situation is the most effective way to ensure your plan stays aligned with your reality.

Take action today and test your own numbers. Please rest assured that any data you enter into this calculator is strictly anonymous. We do not, and cannot, use your information for any purpose, and none of your data is saved.

Use my free Coast FIRE calculator anytime to check your current status and projections, allowing you to better adjust your strategy for the road ahead.

FAQ CoastFIRE Calculator / Coast FI Calculator

Privacy and Data Usage Statement: Please note that all data you enter into this FIRE calculator is not transmitted to our servers or anywhere else. All of your data is anonymous and exists only within your browser.

Related to Coast FIRE Calculator

• FIRE Calculator
• Fat FIRE Calculator
• Barista FIRE Calculator

Disclaimers

This Coast FIRE Calculator is a model, not a prediction. The results are based on the limited information you’ve provided and certain assumptions about the future. All figures are estimates only and are not guaranteed.

It cannot accurately predict your final superannuation balance or retirement income, as these depend on many personal and external factors—such as your individual circumstances, unexpected life events, government Age Pension entitlements, investment returns, tax, and inflation.

The model assumes consistent contributions and stable conditions over time. These assumptions allow you to explore the potential impact of decisions within your control, such as changing your investment strategy.

We recommend reviewing and updating the projections regularly, especially if your situation changes. You can adjust some of the assumptions to better reflect your personal circumstances.