COAST FIRE Calculator

Coast FIRE is one of the most liberating concepts in personal finance — the idea that if you save and invest aggressively enough in your early years, you can eventually stop contributing altogether and simply allow compound growth to carry your portfolio to full financial independence by retirement. The Coast FIRE Calculator helps you determine exactly when that moment arrives. Enter your current age, retirement target, existing investments, expected annual expenses, return rate, inflation rate, and safe withdrawal rate, and the calculator instantly tells you your Coast FIRE number, how many years remain until you reach it, and what your portfolio is projected to be worth when you retire.

This tool is free, works on any device, and requires no registration. Whether you are at the very beginning of your financial independence journey or well into building your investment base, it gives you a precise, personalised picture of where you stand and what it will take to coast the rest of the way.

What Is Coast FIRE?

FIRE stands for Financial Independence, Retire Early — a movement built around the idea of saving and investing at a high rate so that your portfolio eventually generates enough passive income to cover your living expenses indefinitely. Coast FIRE is a specific and particularly appealing variant of this strategy.

With traditional FIRE, the goal is to accumulate enough wealth to retire completely and live off investment returns or withdrawals for the rest of your life. Coast FIRE works differently. The goal is to reach a portfolio size large enough that — even if you never contribute another dollar — compound growth alone will bring your balance to your full retirement target by the time you reach your chosen retirement age. Once you hit your Coast number, you are free to stop saving aggressively. You still need to cover your day-to-day living costs, but you no longer need to funnel additional money into investments. Your existing portfolio does the remaining work on its own.

This distinction opens up a wide range of lifestyle possibilities. Many people who reach their Coast FIRE number choose to shift to part-time work, move into a lower-paying but more meaningful career, take extended time off, or simply redirect their savings toward other goals — all while knowing that retirement is already financially secured.

Who Should Use the Coast FIRE Calculator

Early-Career Savers

If you are in your twenties or thirties and already saving consistently, this calculator shows you how close you may already be to a Coast number — and how dramatically front-loading your investments in early years reduces the total effort required over a lifetime.

Mid-Career Professionals Seeking More Flexibility

If you are approaching your forties and feeling the pressure of high-savings-rate investing, Coast FIRE offers a viable off-ramp. This calculator shows whether your existing portfolio is large enough to coast, or how much further you need to go before you can ease off contributions.

Career Changers and Lifestyle Designers

If you want to move into lower-paid but more fulfilling work — teaching, creative pursuits, non-profit roles, or part-time consulting — knowing your Coast FIRE status tells you whether you can afford to make that move without jeopardising your retirement security.

FIRE Enthusiasts and Financial Planners

For anyone working within the FIRE framework, Coast FIRE is an important milestone on the path to full financial independence. Planners working with clients pursuing early retirement can use this calculator to model scenarios and set actionable intermediate targets.

How to Use the Coast FIRE Calculator

Getting your results is simple and takes less than a minute.

Step 1: Enter Your Current Age

Input your age today. This is the starting point from which the calculator measures how many years your investments have to grow before you reach retirement.

Step 2: Set Your Target Retirement Age

Enter the age at which you intend to stop working entirely and begin drawing on your portfolio. The gap between your current age and your retirement age is the compounding window — the longer it is, the smaller your Coast number needs to be today.

Step 3: Input Your Current Investment Portfolio Value

Enter the total current value of your invested assets — retirement accounts, brokerage accounts, or any other investment holdings you are counting toward your retirement goal. Cash savings and non-invested assets are typically excluded unless you plan to invest them.

Step 4: Enter Your Expected Annual Expenses in Retirement

Estimate how much you expect to spend each year once you retire. This figure drives your full retirement target. If you expect to spend $60,000 per year in retirement, your required portfolio is calculated from that baseline using your safe withdrawal rate.

Step 5: Set Your Expected Investment Return Rate

Enter the annual return rate you expect your portfolio to achieve over time. A commonly used figure for a diversified equity portfolio is 7% in real terms, though you can adjust this to reflect your own asset allocation and risk assumptions.

Step 6: Enter the Inflation Rate

Input your assumed annual inflation rate. This allows the calculator to express your retirement target in today’s dollars, ensuring that the purchasing power of your future portfolio matches your actual retirement spending needs.

Step 7: Set Your Safe Withdrawal Rate

The safe withdrawal rate is the percentage of your portfolio you plan to withdraw annually in retirement without running out of money over a long retirement horizon. A rate of 4% is the most widely cited figure, derived from historical research into sustainable retirement drawdowns, though more conservative planners sometimes use 3% or 3.5%.

Step 8: Click Calculate COAST FIRE

Click the button and your full results appear immediately — your Coast FIRE number, the years remaining until you reach it, your projected retirement portfolio value, and a dynamic growth chart showing your portfolio trajectory from today through to retirement.

Understanding Your Results

Your Coast FIRE Number

This is the portfolio value you need to reach today — or as soon as possible — so that compound growth alone carries you to full financial independence by retirement, with no further contributions required. If your current portfolio already exceeds this number, you have already coasted.

Years to Coast

This figure tells you how many more years of active saving and investing are required before you hit your Coast number, assuming you continue contributing at your current pace. Once this countdown reaches zero, you are free to stop adding to your investments.

Projected Retirement Portfolio

This is the estimated total value of your portfolio at your target retirement age, assuming it grows at your specified return rate from your Coast number forward without any additional contributions. This figure should be sufficient to support your planned annual expenses using your chosen safe withdrawal rate.

Portfolio Growth Trajectory

The interactive chart visualises how your portfolio is expected to grow from your current balance through to retirement age, with your Coast FIRE number marked as a reference point. This visual makes it immediately clear how compound growth accelerates over time and why reaching the Coast number early is so powerful.

The Mathematics Behind Coast FIRE

The power of Coast FIRE lies in the mathematics of compound growth. Money invested early has far more time to multiply than money invested later. A single dollar invested at age 25 at a 7% annual return becomes roughly $15 by age 65 — whereas the same dollar invested at age 45 becomes only around $4 by the same date.

This means that reaching your Coast number at 30 requires a dramatically smaller portfolio than reaching it at 40, because the 30-year-old’s investments have a full decade more to compound. The calculator accounts for this precisely, using your specific ages, return assumptions, and inflation figures to determine the exact number that makes coasting viable for your situation.

Key Concepts Worth Understanding

The Safe Withdrawal Rate

The safe withdrawal rate is the cornerstone of retirement income planning within the FIRE framework. Research suggests that withdrawing 4% of a diversified portfolio annually has historically allowed portfolios to survive 30-year retirements without being depleted. For longer retirements — which are common among early retirees — many planners prefer more conservative rates of 3% to 3.5% to account for the extended drawdown period.

Real vs. Nominal Returns

When setting your return rate, it is worth distinguishing between nominal returns (the raw percentage your investments earn) and real returns (the nominal return minus inflation). Using a real return rate in conjunction with today’s dollar figures for expenses keeps your projections internally consistent and avoids overstating your future purchasing power.

The Flexibility Coast FIRE Creates

One of the most underappreciated aspects of Coast FIRE is not just the financial milestone it represents, but the psychological shift it enables. Knowing that retirement is already secured — that your future self is taken care of — fundamentally changes your relationship with work, risk, and daily financial decisions. Many people find that reaching their Coast number allows them to take professional risks, prioritise wellbeing, and engage with work on their own terms rather than out of financial necessity.

Why the Coast FIRE Calculator Stands Out

Most basic retirement calculators tell you how much you need to save in total. The Coast FIRE Calculator goes further by identifying the specific earlier milestone — the Coast number — at which your ongoing savings effort can stop, your portfolio can take over, and a new chapter of financial freedom can begin. With inputs that cover return rates, inflation, and safe withdrawal assumptions alongside a visual growth trajectory, this tool delivers a complete and nuanced picture of your path to financial independence. It is free, precise, and built for anyone serious about understanding when their money can truly start working for them.