Coast FIRE Calculator
Calculate your Coast FIRE number instantly. Enter your savings, age, and expenses to see weighted and unweighted projections, years to coast, and what-if scenarios.
Coast FIRE Calculator
Find your coast number · Stop contributing · Let compounding do the rest
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For educational purposes only. Not financial advice. Returns are not guaranteed. Consult a qualified financial advisor for personalized guidance.
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About Coast FIRE Calculator
The Coast FIRE Calculator helps anyone pursuing financial independence quickly calculate their Coast FIRE number — the exact amount needed invested today so that compound interest alone grows it to a full retirement nest egg by a target age, with no additional contributions required. It automatically determines your retirement goal, Coast FIRE number, years to coast, savings gap, and projected portfolio growth based on your age, savings, and retirement expenses.
Unlike basic retirement calculators, this tool calculates the precise point at which you can stop saving for retirement entirely — freeing you to work less, earn less, or simply reduce financial stress — while modeling multiple contribution scenarios, a year-by-year savings projection, and adjustable return rate and withdrawal rate assumptions.
Why Use This Tool
The Coast FIRE Calculator is designed to help anyone at any stage of their financial independence journey instantly understand where they stand and what it will take to reach the point where compounding does the work for them. Whether you are just starting to save, already halfway to your goal, or wondering if you have already crossed the coast threshold, the tool provides live results without manual formula work.
It is especially useful for:
- Professionals who want to downshift to lower-paying or part-time work without sacrificing retirement security
- Early savers who want to know how aggressively they need to contribute before they can coast
- Anyone pursuing FIRE who wants to understand the Coast FIRE milestone as a stepping stone to full financial independence
- People evaluating whether a career change, sabbatical, or reduced income is financially viable given their current savings
- Financial planners and individuals comparing how different contribution rates, return assumptions, or retirement ages affect the coast timeline
The Coast FIRE Calculator is designed to be:
- Precise — calculates your exact Coast FIRE number using the correct present-value discounting formula, not a rough estimate
- Live — results update instantly as you change any input, with no calculate button needed
- Scenario-aware — models four contribution levels simultaneously so you can see how saving more or less shifts your coast timeline
- Visual — includes a year-by-year savings projection chart showing the contributing phase and the coasting phase separately
- Flexible — supports custom return rates and withdrawal rates for conservative, moderate, or aggressive planning assumptions
What Is Coast FIRE?
Coast FIRE is a financial independence milestone that sits between active saving and full retirement. The Coast FIRE number is calculated in two steps: first, your retirement nest egg is determined by dividing your expected annual expenses by a safe withdrawal rate — typically 4% based on the Trinity Study, which suggests a portfolio at this size can sustain withdrawals indefinitely. Second, that nest egg is discounted back to today's dollars using compound interest in reverse, producing the amount you need right now for it to grow to the full retirement goal on its own.
Once you reach your Coast FIRE number, your retirement is mathematically on track regardless of whether you contribute another dollar. This is what separates Coast FIRE from traditional retirement planning — instead of accumulating all the way to the finish line, you front-load the compounding work early, then redirect your income entirely toward living expenses, reducing hours, or pursuing work you actually want to do.
Tips for Best Results
To get the most accurate Coast FIRE calculations, keep these tips in mind:
- Enter your retirement expenses in today's dollars — the 7% default return rate is already inflation-adjusted, so no additional adjustment is needed
- Use your total invested assets as current savings — include 401(k), IRA, brokerage, and HSA balances but exclude cash, home equity, and illiquid assets
- Set your retirement age conservatively — a later retirement age lowers your Coast FIRE number significantly because compounding has more time to work
- Adjust the return rate in Advanced Settings if you invest conservatively — index fund investors commonly use 6–7%, while bond-heavy portfolios may use 4–5%
- Use the What-If Scenarios panel to see how doubling contributions for a few years accelerates your coast date compared to the current pace
- Remember that Social Security, pension income, or part-time work in retirement all reduce the nest egg you actually need — your true Coast FIRE number may be lower than the calculator shows
- Revisit the calculator annually as your savings grow — your coast progress percentage updates with every dollar invested
While retirement projections depend on market returns that cannot be guaranteed, the Coast FIRE Calculator provides a reliable framework for understanding your financial independence progress, evaluating the trade-offs between saving aggressively now versus coasting sooner, and making informed decisions about career, lifestyle, and savings priorities at every stage of your financial journey.
How It Works
Understanding the process behind the tool
This Coast FIRE Calculator determines how much you need invested today to achieve Coast FIRE — the point at which your existing savings will grow to fund a full retirement by your target age through compound interest alone, without any additional contributions. It automatically calculates your Coast FIRE number, retirement nest egg, years to coast, savings gap, and projected savings growth based on your inputs.
Factors We Analyze
- Current Age & Retirement Age: The gap between your current age and target retirement age determines how many years compound interest has to work. The longer the runway, the smaller your Coast FIRE number needs to be today.
- Current Savings: Your total invested savings today — the starting point for all projections. The calculator measures your current savings against your Coast FIRE number to determine your progress percentage.
- Annual Contribution: How much you invest per year. Used to calculate how many years of continued saving are needed before you hit your Coast FIRE number and can stop contributing entirely.
- Annual Retirement Expenses: Your expected annual spending in retirement, entered in today's dollars. This is divided by the withdrawal rate to determine the total nest egg you need at retirement.
- Retirement Nest Egg: Calculated as Annual Expenses ÷ Withdrawal Rate (default 4%). This is the total portfolio value you need at retirement age to sustainably fund your lifestyle indefinitely.
- Coast FIRE Number: Calculated by discounting your retirement nest egg back to today's dollars using the formula: Nest Egg ÷ (1 + Return Rate)^Years to Retirement. This is the exact amount you need invested right now to coast to retirement without adding another dollar.
- Annual Return Rate: Defaults to 7% real return — the long-term average inflation-adjusted stock market return. Adjustable in Advanced Settings for conservative or aggressive assumptions.
- Withdrawal Rate: Defaults to 4% based on the Trinity Study safe withdrawal rate, historically sustainable across 30+ year retirements. Adjustable for more or less conservative retirement planning.
- Savings Projection: A year-by-year chart showing your portfolio growth from current age to retirement age — solid line while contributing, dashed line once coasting — plotted against your Coast FIRE target and retirement goal.
- What-If Scenarios: The calculator models four contribution levels — half, current, 1.5×, and double — showing exactly how each changes the number of years to reach your Coast FIRE number.
By combining the Coast FIRE formula with real-time progress tracking, contribution scenario modeling, and a savings projection chart, the calculator helps anyone pursuing financial independence understand exactly where they stand, when they can stop contributing, and how different saving rates accelerate or delay their path to Coast FIRE.
Steps to Use
Enter your current age, target retirement age, current savings, annual contribution, and expected annual expenses in retirement
Optionally open Advanced Settings to adjust the annual return rate (default 7%) or safe withdrawal rate (default 4%) to match your assumptions
View your Coast FIRE number, progress percentage, years to coast, retirement nest egg, and savings gap instantly as you enter each value
Check the What-If Scenarios panel to see how contributing half, the same, 1.5×, or double your current amount changes the years to reach Coast FIRE
Frequently Asked Questions
Get answers to common questions
What is Coast FIRE?
Coast FIRE is a financial independence milestone where you have saved enough that your existing investments will grow to fund a full retirement by your target age through compound interest alone — without any additional contributions. Once you reach your Coast FIRE number, you only need to cover your current living expenses. You no longer need to save for retirement, which frees you to work less, earn less, or pursue lower-paying work you enjoy.
How is the Coast FIRE number calculated?
The Coast FIRE number is calculated in two steps. First, your retirement nest egg is determined by dividing your expected annual expenses by your withdrawal rate — for example, $60,000 ÷ 4% = $1,500,000. Second, that nest egg is discounted back to today's dollars using the formula: Coast FIRE Number = Nest Egg ÷ (1 + Return Rate)^Years to Retirement. This gives the exact amount you need invested right now for it to grow to your full retirement goal without adding another dollar.
What is the difference between Coast FIRE and regular FIRE?
Regular FIRE (Financial Independence, Retire Early) means accumulating enough to retire and live off your investments immediately. Coast FIRE is an earlier milestone — you have enough invested today that compounding will get you to that full retirement number by your target age, but you still need to work to cover current expenses. Coast FIRE lets you stop contributing to retirement while regular FIRE lets you stop working entirely.
What return rate should I use in the calculator?
The calculator defaults to 7% real return, which is the long-term average inflation-adjusted return of a broad stock market index fund. This already accounts for approximately 3% annual inflation, so all figures are expressed in today's dollars. Conservative investors may prefer 5–6%, while those with aggressive equity-heavy portfolios sometimes use 8%. You can adjust this in the Advanced Settings section.
What is the 4% withdrawal rate and why is it the default?
The 4% withdrawal rate comes from the Trinity Study, a widely cited research paper showing that withdrawing 4% of a portfolio annually has historically been sustainable across 30+ year retirements without depleting the portfolio. It is the most commonly used safe withdrawal rate in FIRE planning. The calculator uses 4% as the default but allows you to adjust it in Advanced Settings if you plan a shorter or longer retirement or prefer a more conservative rate.
What should I enter as my current savings?
Enter the total value of your invested assets — including 401(k), IRA, Roth IRA, brokerage accounts, and HSA balances invested in the market. Do not include cash savings, checking or savings account balances, home equity, or other illiquid assets, as these do not compound in the same way and are not available to fund retirement in the traditional FIRE sense.
What does the What-If Scenarios panel show?
The What-If Scenarios panel models four different annual contribution levels — half your current contribution, your current contribution, 1.5 times your current contribution, and double your current contribution — and shows how many years each would take to reach your Coast FIRE number. This helps you see the impact of saving more aggressively now versus coasting sooner at a lower contribution rate.
What does the savings projection chart show?
The projection chart shows your estimated portfolio growth year by year from your current age to your retirement age. The solid line represents the contributing phase — years when you are still adding to your investments. Once your balance crosses the Coast FIRE target, the line switches to dashed to show the coasting phase, where compound growth alone carries the portfolio to your retirement goal. Two reference lines show your Coast FIRE target and full retirement nest egg.
Does the calculator account for Social Security or pension income?
No. The calculator is intentionally conservative and does not include Social Security, pension, or part-time income in retirement. If you expect income from any of these sources, your actual required nest egg is lower than what the calculator shows — meaning your true Coast FIRE number is smaller and you may already be closer to coasting than the results suggest.
How is Coast FIRE different from Barista FIRE?
Coast FIRE means your investments will grow to cover full retirement on their own — you just need to earn enough to cover current living expenses, with no retirement saving required. Barista FIRE is similar but specifically refers to working part-time in a lower-stress job (historically associated with jobs that offer health benefits) where your part-time income covers expenses while your investments coast. The two concepts overlap significantly; the main distinction is that Barista FIRE emphasizes the part-time work arrangement.
Is the Coast FIRE Calculator free to use?
Yes, the Coast FIRE Calculator is completely free to use. You can calculate your Coast FIRE number, view your savings projection, model contribution scenarios, and track your progress toward financial independence without creating an account or signing up.