Coast FIRE Calculator - Financial Independence Tool

Introduction

Coast FIRE is a milestone on the path to financial independence where you've saved enough that your investments will grow to your full retirement number on their own — even if you never invest another dollar. Once you hit your Coast FIRE number, compound growth does the heavy lifting, and you only need to earn enough to cover your current living expenses. This frees you to take a lower-paying job, work part-time, or simply remove the pressure of aggressive saving from your life.

Our Coast FIRE Calculator helps you find three key things: your FIRE target number (the total portfolio you need to retire), your Coast FIRE number (how much you need saved right now so growth alone finishes the job), and your Coast FIRE age (when your portfolio crosses that threshold based on your monthly contributions). Just enter your age, savings, contributions, expected returns, and spending goals. The calculator adjusts every result for inflation so you see numbers in today's dollars — giving you an honest picture of your future purchasing power. A year-by-year table and interactive chart show exactly how your portfolio stacks up against the Coast FIRE curve over time.

How to Use Our Coast FIRE Calculator

Enter your age, savings, and retirement goals below, and this calculator will tell you your Coast FIRE number — the amount you need saved so your money can grow to your full retirement target on its own, with no more contributions needed.

Current Age — Enter how old you are right now. This is the starting point for all projections.

Target Retirement Age — Enter the age when you want to stop working and begin living off your investments. If you're unsure what age is realistic, try running scenarios with our Retirement Calculator as well.

Current Invested Assets — Enter the total value of your invested accounts, such as a 401(k), Roth IRA, or brokerage account. Do not include your emergency fund, checking account, or money that is not invested.

Monthly Contribution — Enter how much money you add to your investments each month. This is the amount you save and invest on a regular basis.

Annual Spending in Retirement — Enter how much money you expect to spend each year once you retire. Think about your living costs, healthcare, travel, and hobbies.

Pre-Retirement Annual Return — Enter the yearly return you expect your investments to earn before you retire. A common estimate for a stock-heavy portfolio is 7%. You can use our Investment Calculator to model different return scenarios.

Post-Retirement Annual Return — Enter the yearly return you expect your investments to earn after you retire. This is usually lower than your pre-retirement return because many people shift to safer investments during retirement.

Expected Inflation Rate — Enter the rate at which you expect prices to rise each year. A typical estimate is 3%. The calculator uses this to show all results in today's dollars so you can see the real purchasing power of your money. Our Inflation Calculator can help you understand how inflation erodes purchasing power over time.

Safe Withdrawal Rate (SWR) — Enter the percentage of your portfolio you plan to withdraw each year in retirement. The 4% rule is a widely used starting point, meaning you would take out 4% of your savings per year to cover living expenses.

What Is Coast FIRE?

Coast FIRE is a milestone on the path to financial independence where you have saved enough money that, even if you never invest another dollar, your portfolio will grow on its own to support your retirement by your target age. Once you hit your Coast FIRE number, compound interest does all the heavy lifting. You still need to cover your living expenses, but you no longer need to save for retirement.

How Coast FIRE Works

The idea behind Coast FIRE is simple. Money that is invested grows over time thanks to compound returns. If you save aggressively early in life, there comes a point where your investments will compound to a large enough amount by retirement age — without any extra contributions. At that point, you are "coasting." You could switch to a lower-paying job you enjoy more, work part-time, or simply stop stressing about your savings rate. The Rule of 72 Calculator is a quick way to estimate how long it takes for your money to double at a given return rate — a useful sanity check when thinking about Coast FIRE timelines.

Key Numbers You Need to Know

FIRE Target Number: This is the total amount you need in your portfolio to retire and live off your investments. It is calculated by dividing your expected annual spending in retirement by your safe withdrawal rate (SWR). For example, if you plan to spend $40,000 per year and use a 4% withdrawal rate, your FIRE target is $1,000,000.

Coast FIRE Number: This is how much you need to have saved right now so that it grows to your FIRE target by retirement — with zero additional contributions. It depends on your age, your target retirement age, and your expected real rate of return (investment returns minus inflation). You can explore how different compounding scenarios affect growth with our Future Value Calculator.

Coast FIRE Age: If you haven't yet reached your Coast FIRE number, this tells you the age at which your growing portfolio (with continued contributions) will cross the Coast FIRE threshold.

Why Inflation Matters

A dollar today will not buy the same amount of goods 30 years from now. That is why this calculator adjusts all values for inflation. It uses the "real" rate of return, which is your investment return minus inflation. This way, every number you see reflects actual purchasing power in today's dollars, giving you an honest and useful picture of your future finances. To see the concrete impact of inflation on a specific dollar amount over time, try the Inflation Calculator.

The Safe Withdrawal Rate

The safe withdrawal rate is the percentage of your portfolio you pull out each year in retirement. The most common starting point is the 4% rule, which comes from a well-known retirement study called the Trinity Study. It found that withdrawing 4% of your portfolio per year, adjusted for inflation, had a high chance of lasting at least 30 years. If you want to be more conservative or plan for a longer retirement, you might choose a lower rate like 3.5% or 3%.

How to Use Your Results

If the calculator shows you have already reached Coast FIRE, that means your current savings will grow to your FIRE target on their own. Any extra money you invest from this point forward is a bonus that could let you retire earlier or with more spending flexibility. Consider using our Net Worth Calculator to get a complete snapshot of where you stand financially.

If you haven't reached Coast FIRE yet, the calculator shows you exactly when you will — and how much you need to keep saving each month to get there. The year-by-year table and chart let you track your progress at every age along the way. If you're also carrying debt that competes with your saving goals, tools like the Debt Snowball Calculator or Debt Avalanche Calculator can help you build a payoff plan so more of your income goes toward investments.

Tips to Reach Coast FIRE Faster

Start early. The younger you are, the more time compound growth has to work. Even small amounts invested in your 20s can make a huge difference. Use the Compound Interest Calculator to see how powerful early contributions truly are.
Increase your savings rate. Bumping your monthly contribution by even $100 can shave years off your Coast FIRE age. A Savings Calculator can help you model different contribution levels.
Keep expenses in check. A lower annual spending target means a smaller FIRE number, which means a smaller Coast FIRE number.
Stay invested. Pulling money out or sitting in cash slows compound growth. Keep your invested assets working for you through market ups and downs. If you use a dollar-cost averaging strategy, our DCA Calculator can show you how consistent investing smooths out volatility over time.
Maximize tax-advantaged accounts. Contributions to your 401(k), Roth IRA, or HSA grow tax-free or tax-deferred, letting more of your returns compound without being reduced by taxes.

Frequently asked questions

What is the difference between Coast FIRE and regular FIRE?

Regular FIRE means you have saved enough to retire right now and live off your investments. Coast FIRE means you have saved enough that your money will grow to your full retirement number on its own by your target age — but you still need to work to cover your current living expenses. Coast FIRE is a halfway point. You stop saving for retirement but keep earning enough to pay your bills today.

How is the Coast FIRE number calculated?

The calculator first finds your FIRE target by dividing your annual retirement spending by your safe withdrawal rate. Then it figures out how much money you would need today so that it grows to that FIRE target by your retirement age using compound growth. The formula is: Coast FIRE Number = FIRE Target ÷ (1 + real rate of return) ^ years until retirement. The real rate of return is your investment return minus inflation.

What should I do after I reach Coast FIRE?

Once you reach Coast FIRE, you no longer need to save for retirement. Your investments will grow to your target on their own. You can keep working but switch to a job you enjoy more, work fewer hours, or take a pay cut without hurting your retirement plan. You just need to earn enough to cover your current bills. Any extra money you invest after Coast FIRE lets you retire even earlier or with more spending room.

Why are all the results shown in today's dollars?

Showing results in today's dollars makes them easier to understand. A million dollars 30 years from now will not buy what a million dollars buys today because of inflation. By adjusting for inflation, the calculator shows you the real purchasing power of your money. This gives you an honest picture of what your savings will actually be worth when you retire.

What is a good safe withdrawal rate to use?

The most common starting point is 4%, based on the Trinity Study. This means you withdraw 4% of your portfolio each year in retirement. For a retirement lasting longer than 30 years, such as early retirement, a lower rate like 3.5% or 3% is safer. A higher rate like 4.5% or 5% is riskier but means you need less money saved. Choose a rate based on how long your retirement might last and how flexible your spending can be.

What rate of return should I use for pre-retirement?

A 7% nominal return is a common estimate for a portfolio heavily invested in stocks, based on long-term historical averages of the U.S. stock market. If your portfolio includes a lot of bonds or other conservative investments, you might use a lower number like 5% or 6%. The calculator subtracts inflation from this number to get your real rate of return.

Why is the post-retirement return lower than the pre-retirement return?

Many people shift to a more conservative mix of investments after they retire. They move some money from stocks into bonds and other safer assets to reduce risk. Safer investments typically earn lower returns. A common post-retirement return estimate is around 4% to 5% before inflation. You can set both rates to the same value if you plan to keep the same investment mix throughout retirement.

What does the Coast FIRE curve on the chart mean?

The Coast FIRE curve shows the minimum amount you need saved at each age so that your money grows to your FIRE target by retirement — with no more contributions. It starts low when you are young (because you have more years of growth ahead) and rises to equal the full FIRE target at your retirement age. When your portfolio line crosses above this curve, you have reached Coast FIRE.

Can I reach Coast FIRE if I start late?

Yes, but it is harder. When you start later, your money has fewer years to compound, so your Coast FIRE number is higher and closer to the full FIRE target. You may need to save more each month or plan for a later retirement age. The calculator lets you adjust all of these inputs so you can find a plan that works for your situation.

Should I include my home value in current invested assets?

No. Only include assets that are actually invested and growing, like money in a 401(k), IRA, Roth IRA, or brokerage account. Your home, car, emergency fund, and checking account should not be counted. These assets either do not earn investment returns or are not available to fund your retirement withdrawals.

What does the surplus or shortfall result mean?

The surplus or shortfall shows the difference between your projected portfolio value at retirement and your FIRE target number. A positive surplus means you are on track to have more than you need — you could retire earlier, spend more, or have a bigger safety cushion. A shortfall means your projected savings will fall short of your target, and you may need to save more or adjust your plans.

How does changing inflation affect my Coast FIRE number?

Higher inflation reduces your real rate of return, which means your money grows slower in terms of purchasing power. This makes your Coast FIRE number higher because you need more money today to reach the same goal. Lower inflation has the opposite effect — your real returns are stronger and your Coast FIRE number drops. Even a small change in inflation can make a big difference over 20 or 30 years.

What if I want to retire earlier than 65?

Just lower the target retirement age in the calculator. Retiring earlier means your money has fewer years to grow, so both your Coast FIRE number and the amount you need to save each month will go up. You may also want to use a lower safe withdrawal rate since your retirement will last longer. Try different ages to see what is realistic for your savings and contributions.

Is Coast FIRE the same as Barista FIRE?

They are very similar. Coast FIRE means your investments will grow to your retirement goal without more contributions, and you just need to cover current expenses. Barista FIRE usually refers to working a part-time or low-stress job — sometimes one that provides health insurance — to cover those expenses. Barista FIRE is basically how many people live after reaching Coast FIRE.

Does this calculator account for Social Security or pensions?

No. This calculator does not include Social Security, pensions, or other income sources. It assumes your investments need to fully fund your retirement spending. If you expect to receive Social Security or a pension, your actual FIRE target could be lower. You can account for this by reducing the annual spending number by the amount you expect to receive from those sources.