Coast FIRE Calculator

Begin by entering your current financial situation. Your Current Age and Current Savings establish the starting point for the projection. Include all invested assets intended for retirement, such as balances in a 401(k), Roth IRA, brokerage account, or other investment vehicles.

Next, define your retirement goal in the FIRE Target section. Enter your Target Retirement Age, which is when you plan to start living off your investments. Then, input your estimated Annual Expenses in Retirement in today's dollars. This is a critical number; if you're unsure, our retirement expense calculator can help you create a detailed budget. Finally, set your Withdrawal Rate, which determines how much you'll pull from your portfolio each year. A 4% rate is a common starting point based on the 4% rule.

Then, set your Growth Assumptions. The Annual Return is your expected average return on investments before any fees or inflation. The Inflation Rate is used to project how much your future expenses will increase over time. The difference between these two is the "real return," which is crucial for Coast FIRE calculations. Learn more about how inflation affects retirement savings.

For a more tailored projection, open the Advanced settings to adjust your Life Expectancy. This helps contextualize the length of the retirement you are planning for.

Current Age and Current Savings

Your age and current savings are the foundation of the calculation. A younger age and higher savings balance dramatically lower the amount needed to reach Coast FIRE, as your money has more time to compound. When entering your savings, include all long-term investment accounts you plan to use to fund retirement.

Target Retirement Age

This is the age you plan to fully retire and begin withdrawing from your portfolio. A later retirement age gives your investments more time to grow, significantly reducing your Coast FIRE number. You can experiment with different ages to see the impact—the retirement age calculator can help you see how this single factor changes your entire plan.

Annual Expenses in Retirement

This is your estimated yearly spending in retirement, expressed in today's dollars. The calculator will adjust this figure for inflation to determine your actual spending needs at your target retirement age. Accurately estimating this is key to a meaningful result. A good starting point is 80% of your current income, but a detailed retirement budget provides a much better estimate.

Withdrawal Rate

The withdrawal rate is the percentage of your portfolio you plan to withdraw each year in retirement. This rate, applied to your final nest egg, must be enough to cover your annual expenses. A lower, more conservative rate (like 3.5% or 4%) increases the chances your money will last. You can test different rates with our 4% rule retirement withdrawal calculator.

Annual Return and Inflation Rate

The annual return is your assumed average rate of growth from your investments. This should be a long-term, conservative estimate. The inflation rate is the assumed average rate at which the cost of living will increase. The calculator uses both to determine the "real" (inflation-adjusted) rate of return, which is what truly grows your purchasing power over time. Using an inflation-adjusted retirement calculator can show the powerful, and often underestimated, effect of inflation.

Life Expectancy

This advanced input helps frame the total length of your retirement. While the Coast FIRE calculation focuses on reaching a specific number by retirement, your life expectancy determines how long that number ultimately needs to last. Planning for a longer life provides a greater margin of safety.

The calculator's methodology is based on the core principles of financial independence and compound growth. It works backward from your retirement goal to determine what you need saved today.

1. Calculate the FI Number: First, it determines your Financial Independence (FI) number. This is the total portfolio value you'll need at your target retirement age. It calculates this by projecting your annual expenses forward with inflation and then dividing that future spending need by your chosen withdrawal rate.
2. Calculate the Coast FIRE Number: Next, it calculates your Coast FIRE number. This is the present value of your FI number. It takes the future FI number and discounts it back to today's dollars using your assumed real rate of return (annual return minus inflation) over the number of years between your current age and your target retirement age. This result is the amount of money that, if invested today, should grow to your FI number by retirement without any additional contributions.
3. Project Your Growth: The calculator also projects the future value of your current savings, assuming they grow at the nominal annual return rate. This allows you to see if your current trajectory will meet or exceed your FI number by retirement, even if you stop saving today.

The final score and analysis compare your current savings to your calculated Coast FIRE number to show you exactly where you stand.

The calculator uses several key formulas to determine your Coast FIRE status. The logic flows from your future needs back to your present situation.

Financial Independence (FI) Number

This is the total nest egg you need on the day you retire.

Years to Retirement = Target Retirement Age - Current Age
Inflation-Adjusted Expenses = Annual Expenses in Retirement x (1 + Inflation Rate) ^ Years to Retirement
FI Number = Inflation-Adjusted Expenses / (Withdrawal Rate / 100)

Real Rate of Return

This is the rate at which your investments grow after accounting for inflation.

Real Return = (1 + Annual Return) / (1 + Inflation Rate) - 1

Note: The code uses a simplified (Annual Return - Inflation Rate) for its calculation, which is a common and reasonable approximation.

Coast FIRE Number

This is the present value of your FI Number, representing the amount you need invested today.

Coast FIRE Number = FI Number / (1 + Real Return) ^ Years to Retirement

Projected Savings at Retirement

This formula shows what your current savings could grow to by your retirement age if you make no further contributions.

Projected at Retirement = Current Savings x (1 + Annual Return) ^ Years to Retirement

Coast FIRE is a milestone on the path to financial independence. It's the point at which you have enough money in your retirement accounts that, without contributing another cent, your portfolio will grow to support you in traditional retirement.

Think of it like riding a bicycle to the top of a big hill. The work you do pedaling up is your active saving phase. Reaching the top is hitting your Coast FIRE number. From there, you can stop pedaling (saving) and simply "coast" down the other side, letting momentum (compound growth) carry you to your destination (your full retirement fund).

After reaching Coast FIRE, you still need to work to cover your current living expenses, but the pressure to save for the future is gone. This unlocks incredible flexibility. You could switch to a lower-stress job, work part-time, start a business, or take a mini-retirement, all with the peace of mind that your retirement is already secured. It separates the goal of "earning to live" from "earning to save for retirement." For a deeper dive, read our guide to Coast FIRE explained.

The FIRE movement isn't one-size-fits-all. Coast FIRE is just one of several popular approaches.

• Traditional FIRE: The goal is to accumulate 25x your annual expenses, allowing you to fully retire, often decades early. This requires a very high savings rate. Use the early retirement calculator to model this path.
• Lean FIRE: This is a version of traditional FIRE for minimalists. Retirees live on a smaller-than-average budget (e.g., under $40,000 per year), which means the FI number is lower and easier to reach. See the Lean FIRE calculator.
• Fat FIRE: The opposite of Lean FIRE. This is for high earners who want to retire early without sacrificing a lavish lifestyle, requiring a much larger nest egg (e.g., $5 million or more).
• Barista FIRE: This is a strategy where someone retires from their primary career but takes on a part-time job, often for benefits like health insurance, to cover current expenses while their retirement portfolio grows. It's very similar to the lifestyle one might live after achieving Coast FIRE.

Coast FIRE is unique because it's not an end state but a powerful intermediate goal. It's the "work optional" phase that bridges the gap between a high-stress accumulation phase and full retirement.

Your results provide a clear snapshot of your Coast FIRE journey.

• Score Gauge: This gives you an immediate sense of your progress. A score of 100 or more means you've successfully reached Coast FIRE. A lower score shows how far you have to go.
• Coast FIRE Number: This is your primary target. It's the amount you need invested today to be on track.
• FI Number: This is the total amount you'll need at your target retirement age. It's your ultimate destination.
• Surplus / Deficit: This shows you, in exact dollar terms, how much you are over or under your Coast FIRE number.
• Projected at Retirement: This key figure shows what your current savings will likely grow into by retirement age. If this number is higher than your FI Number, you're in an excellent position.
• Passive Growth vs. FI Target Chart: This visualizes your journey. The "Your Savings" line shows your money compounding over time. The "FI Target" line shows your goal growing with inflation. Ideally, your savings line will meet or cross the target line by your retirement age.
• Coast FIRE Number by Age Chart: This powerful chart illustrates the magic of compounding. It shows how much lower your Coast FIRE number would be if you started at a younger age, reinforcing the benefit of starting early.

If the calculator shows a deficit, don't be discouraged. You have several levers you can pull to reach Coast FIRE.

1. Increase Your Savings: The most direct method. Focus on increasing your savings rate to build your initial nest egg faster. Use a 401(k) contribution calculator to maximize your workplace plan.
2. Adjust Your Retirement Age: Pushing your target retirement age back by even a few years can dramatically lower your Coast FIRE number because it gives your investments more time to grow.
3. Reduce Future Expenses: A lower annual spending target in retirement reduces your FI number, which in turn lowers the Coast FIRE number you need to hit today.
4. Review Your Assumptions: Ensure your expected investment return is realistic. A slightly more aggressive (but still appropriate) asset allocation might increase your long-term return, but be mindful of the added risk. Conversely, a lower inflation assumption also helps, but be realistic.

1. Forgetting to Re-evaluate: Your Coast FIRE number is not static. It changes as your goals, income, and market returns fluctuate. Re-run the calculation at least once a year.
2. Ignoring Healthcare Costs: Your FI number must be large enough to cover all expenses, including healthcare. This is a major expense, especially if you retire before Medicare eligibility at age 65. Use the retirement healthcare cost calculator to get a better estimate.
3. Being Too Optimistic: Using an unrealistically high investment return or a low inflation rate can make your goal seem closer than it is. It's better to plan conservatively.
4. Cashing Out: The entire strategy depends on letting your investments grow untouched for decades. Withdrawing money early from your 401(k) or IRA will derail the plan.
5. Stopping All Savings Prematurely: Coast FIRE means you can stop saving for retirement. You may still want to save for other goals like a house, a car, or a child's education.