FIRE Calculator – Plan Financial Independence & Early Retirement
The FIRE Calculator from MyTimeCalculator is built for anyone serious about financial independence and early retirement. FIRE stands for “Financial Independence, Retire Early” and it focuses on building an investment portfolio large enough to cover your living expenses indefinitely. This calculator helps you estimate your target FIRE number, how many years it may take to reach it, your potential retirement age, and the amount you can safely withdraw each year.
Instead of relying on guesswork, rules of thumb, or rough mental math, this FIRE calculator breaks your journey into clear numbers. You can experiment with different savings rates, expected returns, safe withdrawal rates, and spending levels to see how they affect your path to financial independence.
How the FIRE Calculator Works
This calculator offers four main modes: FIRE Number, Years to FIRE, FIRE Age, and Safe Withdrawal. Each mode answers a focused FIRE planning question, while still connecting to the bigger picture. Together, they form a simple framework for understanding how much you need, how long it might take, and what kind of lifestyle your portfolio can support.
The interface is designed to stay consistent with other MyTimeCalculator tools: you enter your current savings, monthly contributions, expected return, and spending assumptions, then the calculator instantly shows your results. You can run multiple scenarios quickly, making it ideal for both beginners and advanced FIRE planners.
Mode 1: FIRE Number – How Much Do You Need to Reach Financial Independence?
Your FIRE number is the estimated portfolio value at which your investments can fund your lifestyle indefinitely, based on a chosen safe withdrawal rate. For many people, this is the most important piece of the FIRE puzzle: it tells you the target you are aiming for.
Formula for FIRE Number
For example, if you expect to spend $40,000 per year in retirement and choose a 4% safe withdrawal rate, your FIRE number is:
This is the popular “25x rule” – you multiply annual spending by 25. If you choose a more conservative rate like 3.5% or 3%, the required portfolio increases, but so does your margin of safety.
What the FIRE Number Mode Shows
- Your FIRE number (target portfolio value).
- The spending multiple: how many times your annual spending your portfolio represents.
- Estimated annual withdrawal at FIRE (based on the safe withdrawal rate).
- Estimated monthly withdrawal at FIRE.
Mode 2: Years to FIRE – How Long Will It Take?
Once you know your FIRE number, the next step is estimating how long it might take to reach it. The Years to FIRE mode uses your current portfolio value, monthly contributions, and expected annual return to model compound growth over time.
How Years to FIRE Is Estimated
The calculator uses a simple compound growth model with regular monthly contributions:
Where rmonthly is your annual return divided by 12. The calculator iterates month by month until your balance reaches or exceeds the target FIRE number or a maximum planning horizon (for example, around 80 years is used as a cap in the model).
What the Years to FIRE Mode Shows
- Approximate years and months until your portfolio reaches the target FIRE number.
- Portfolio value at the moment FIRE is achieved.
- Total new contributions (excluding growth) made along the way.
- A note if the target cannot be reached within a realistic time horizon at the current savings rate.
This mode is useful when testing “what if” questions: what happens if you save an extra $200 per month, increase your expected return by investing more aggressively, or reduce your FIRE number by lowering future expenses?
Mode 3: FIRE Age – At What Age Could You Reach Financial Independence?
The FIRE Age mode adds one more key dimension: your current age. By combining your current age, savings, contributions, expected return, spending goal, and safe withdrawal rate, the calculator estimates the age at which you might reach FIRE.
Steps in the FIRE Age Calculation
- Compute your FIRE number from target annual spending and safe withdrawal rate.
- Simulate monthly portfolio growth using current savings, monthly contributions, and expected return.
- Track how many years it takes to reach the FIRE number.
- Add those years to your current age to estimate your age at FIRE.
The FIRE Age mode is particularly motivating because it turns abstract financial numbers into a real-life timeline. You can see how increasing savings, reducing spending, or adjusting your safe withdrawal rate could move your FIRE age forward or backward.
What the FIRE Age Mode Shows
- Your target FIRE number based on spending and withdrawal rate.
- Estimated age at which you may reach financial independence.
- Years remaining until FIRE (approximate timeline).
- Portfolio value at the time FIRE is reached.
Mode 4: Safe Withdrawal – How Much Can You Spend in Retirement?
The Safe Withdrawal mode answers a common FIRE question: “If I already have a portfolio, how much can I safely spend per year?” By entering your portfolio value and withdrawal rate, the calculator estimates your annual, monthly, and daily income from investments.
Safe Withdrawal Formulas
This mode is useful both for people already retired and for those testing whether their target portfolio can support a specific lifestyle. For example, if you have $900,000 invested and plan to withdraw 4% per year, your estimated annual income is $36,000, or $3,000 per month.
Why Use a FIRE Calculator Instead of Simple Rules of Thumb?
FIRE planning often starts with simple rules like “25x annual spending” or “save 50% of your income.” But in real life, people have different incomes, savings rates, investment returns, time horizons, and risk tolerances. A dedicated FIRE calculator lets you build a plan based on your actual numbers.
With this calculator, you can:
- Estimate how much money you need for financial independence based on your lifestyle.
- Understand how long it might realistically take to reach FIRE at your current savings rate.
- Experiment with different withdrawal rates (3%, 3.5%, 4%, etc.).
- See the impact of higher or lower investment returns on your FIRE timeline.
- Translate portfolio values into real monthly spending power.
Example Scenarios Using the FIRE Calculator
Example 1: Finding Your FIRE Number
Suppose you want to spend $45,000 per year in early retirement and choose a 3.75% safe withdrawal rate. Your FIRE number is:
This means you would aim for a portfolio of about $1.2 million to support your lifestyle at that withdrawal rate.
Example 2: Estimating Years to FIRE
You currently have $80,000 invested, contribute $1,500 per month, and expect a 7% annual return. Your target FIRE number is $1,000,000. The calculator simulates compound growth and might show that you could reach FIRE in around 17–19 years, depending on exact assumptions and rounding.
Example 3: Estimating Your FIRE Age
You are 28 years old with $40,000 invested, contributing $1,200 per month at an expected 7% return. You want to spend $35,000 per year in retirement and choose a 4% withdrawal rate. The calculator estimates a FIRE number of $875,000 and may show that you reach this at around age 47, giving an approximate FIRE age and years remaining.
Example 4: Safe Withdrawal from an Existing Portfolio
If you already have a $1,200,000 portfolio and plan to withdraw 3.5% per year, the calculator shows:
- Annual safe withdrawal ≈ $42,000
- Monthly withdrawal ≈ $3,500
- Daily withdrawal ≈ $115 (approximate)
This helps you check whether your current wealth can support your current or desired spending level.
How to Use This FIRE Calculator Effectively
- Start with the FIRE Number mode to understand the size of portfolio you need based on your desired lifestyle.
- Use the Years to FIRE mode to see whether your savings rate and expected returns are aligned with your target timeline.
- Switch to the FIRE Age mode to turn those numbers into a real-life age estimate.
- Use the Safe Withdrawal mode to test different withdrawal rates and see how they affect your retirement income.
- Run multiple scenarios: higher savings, lower spending, different returns, or more conservative withdrawal rates.
- Revisit your assumptions over time as your income, savings rate, or goals change.
Important Considerations and Limitations
While this FIRE calculator is a powerful planning tool, it is still a simplified model:
- Investment returns are assumed to be constant over time, but actual markets are volatile.
- Inflation, taxes, and changing expenses are not modeled in detail.
- Healthcare, major one-time purchases, and other life events can affect your true FIRE timeline.
- Safe withdrawal rate research is based on historical data and cannot guarantee future outcomes.
For critical decisions, consider combining this calculator with professional financial advice and more detailed planning tools. Use it as a starting point to understand the trade-offs between savings rate, time, and lifestyle.
Related Tools from MyTimeCalculator
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FIRE Calculator FAQs
Frequently Asked Questions About FIRE & Early Retirement
Find answers to common questions about FIRE numbers, safe withdrawal rates, timelines to financial independence, and early retirement planning.
A FIRE calculator is a planning tool that helps you estimate your financial independence number, how long it may take to reach it, and how much income you can safely withdraw in retirement without running out of money too early.
You calculate your FIRE number by dividing your target annual spending by your chosen safe withdrawal rate. For example, if you plan to spend $40,000 per year and use a 4% withdrawal rate, your FIRE number is $1,000,000.
Many FIRE enthusiasts start with a 4% withdrawal rate based on historical research, but some prefer more conservative rates like 3%–3.5% for longer retirements or higher safety margins. The best rate depends on your time horizon, risk tolerance, and investment mix.
No calculator can guarantee future results. This FIRE calculator uses simplified assumptions about returns and withdrawals. It is a planning tool to help you explore scenarios, not a guarantee of outcomes. Real-world results depend on market performance, inflation, taxes, and your spending behavior.
Yes. Even if you target traditional retirement ages, the FIRE calculator helps you understand how savings, returns, and spending interact. It is simply a financial independence tool that works for both early and traditional retirement goals.
It is a good idea to review your FIRE plan at least once or twice a year, or whenever you experience a major life change such as a new job, income change, relocation, or shift in financial goals. Updating your numbers regularly keeps your plan aligned with reality.