Is my financial data uploaded to a server?

No, the calculation happens entirely in your browser using JavaScript; nothing is transmitted or stored anywhere.

What is a safe withdrawal rate, and why does it matter so much?

It's the percentage of your portfolio you plan to withdraw annually in retirement; it matters because it directly determines how large a portfolio you need relative to your spending, with lower rates requiring proportionally larger portfolios.

Why does the commonly cited 4% rule imply a number of 25 times expenses?

Mathematically, withdrawing 4% annually means the portfolio is 25 times the annual withdrawal amount, since 1 divided by 0.04 equals 25.

Is the 4% withdrawal rate guaranteed to be safe?

No, it's based on historical market analysis over specific past periods and isn't a guarantee for any individual's future retirement, which is why some practitioners choose a more conservative rate for additional safety margin.

How does this differ from a standard retirement calculator?

Standard retirement calculators often assume a traditional retirement age around 65; FIRE calculations are typically used for much earlier, self-directed retirement timelines based on hitting a specific portfolio target rather than a specific age.

Should I include Social Security or pension income in this calculation?

This tool focuses on the core FIRE number derived purely from your invested portfolio and expenses; if you expect other income sources, you may want to factor those in separately when interpreting the result.

How often should I recalculate my FIRE number?

Recalculating periodically, such as annually or whenever expenses or savings change meaningfully, keeps the target and timeline aligned with your actual current financial situation.

Does this account for inflation?

The growth rate and expense figures you enter should ideally already reflect your own assumptions about inflation, since the calculation itself doesn't separately model inflation unless you build it into those inputs.

FIRE Calculator Guide

FIRE Calculator estimates your Financial Independence number and retirement timeline in your browser, based on savings, expenses, and growth assumptions.

FIRE Calculator estimates the core numbers behind the Financial Independence, Retire Early movement: how much invested wealth you'd need to sustainably cover your living expenses without relying on traditional employment income, and roughly how long it would take to get there given your current savings rate. The central idea behind FIRE is straightforward even though the math has some nuance — once your invested assets are large enough that a conservative, sustainable withdrawal rate covers your annual spending indefinitely, you've reached a number where continuing to work becomes optional rather than necessary.

This tool calculates your FIRE number, the total invested portfolio size needed to sustain your expenses, based on your annual spending and a chosen safe withdrawal rate, and then projects a timeline to reach that number using your current savings, monthly contribution rate, and an assumed average investment growth rate. Everything is calculated directly in your browser using JavaScript, with no account or financial data stored anywhere beyond your current session.

The withdrawal rate assumption is the single most consequential number in the whole calculation, since it determines how large a portfolio you actually need relative to your spending — a commonly referenced rate around 4% implies a FIRE number of roughly 25 times annual expenses, while a more conservative rate produces a larger required number but a higher margin of safety against market downturns and a longer retirement horizon. There's genuine, ongoing debate among practitioners about which withdrawal rate is appropriately conservative for any given retirement length, and this tool lets you adjust that assumption directly rather than baking in a single fixed answer.

Like any long-term financial projection, the result here depends heavily on assumptions that won't play out with certainty — actual investment returns vary year to year, expenses change over decades, and unexpected life events happen — so the calculated number and timeline are best treated as a planning estimate to revisit periodically rather than a fixed, guaranteed outcome locked in from a single calculation today.

How to calculate your FIRE number and timeline

Enter your annual expenses. Provide your exact current annual spending figure carefully, ideally based on actual tracked expenses rather than a rough mental guess pulled from memory, since this single number directly drives your entire FIRE target through the underlying withdrawal rate calculation entirely. Underestimating annual expenses is one of the most common ways this whole calculation ends up producing an unrealistically low and overly optimistic FIRE number. Reviewing a few months of actual bank or credit card statements rather than relying purely on memory is the most reliable way to arrive at a genuinely accurate annual figure.
Choose your safe withdrawal rate. Select precisely the annual withdrawal rate you're genuinely comfortable relying on throughout retirement, with a commonly referenced figure around 4% generally being a frequent, popular starting point, though noticeably more conservative rates are often deliberately chosen for longer retirement horizons or for extra safety margin overall. This one single assumption genuinely has an outsized, significant effect on your final calculated FIRE number, so it's worth genuinely thinking through rather than accepting a default without consideration. Trying a couple of different rates side by side and comparing the resulting numbers is a reasonable way to get an intuitive feel for how sensitive the whole calculation actually is to this one assumption.
Enter your current savings and monthly contributions. Provide your exact current total invested savings and precisely how much you're actually able to contribute toward investments each month, since these two specific figures together genuinely determine exactly how quickly your overall portfolio actually grows toward the calculated target number. Being genuinely realistic about a contribution rate you can actually sustain consistently over many years matters far more than entering an overly aspirational number you might not actually maintain long-term. Even modest, consistent increases to a monthly contribution can shift the projected timeline more noticeably than people often expect, since the effect compounds meaningfully over many years of investing.
Set an assumed growth rate. Enter precisely the average annual investment growth rate you're actually assuming for this entire projection, while genuinely recognizing that actual market returns vary quite significantly year to year, even though they do tend to average out over sufficiently long periods. A more conservative growth assumption naturally and reliably produces a noticeably longer, more cautious timeline estimate overall, while an optimistic one produces a shorter but less certain projection. Many practitioners choose to model a few different growth scenarios side by side, from conservative to optimistic, to understand the realistic range of possible outcomes rather than anchoring to just one single number.
Review your FIRE number and projected timeline. Carefully look at the calculated FIRE number — your specific target portfolio size — alongside the estimated total number of years it would take to reach it given your current overall trajectory. Use this carefully as an ongoing, evolving planning reference point to revisit periodically going forward, adjusting your savings rate, expense assumptions, or withdrawal rate as your actual financial situation and goals evolve over time. Treating both figures as a living estimate that gets revisited periodically, rather than a one-time calculation set in stone, leads to a more useful and ultimately more accurate long-term plan.

Use Cases

Setting a long-term financial independence target: Calculate a FIRE number as a concrete long-term target to work toward, rather than pursuing financial independence without a defined goal.
Comparing timelines under different savings rates: Adjust the monthly contribution amount to see how increasing savings rate shortens the estimated timeline to reach financial independence.
Evaluating the impact of a more conservative withdrawal rate: Compare the resulting FIRE number under a more conservative withdrawal rate assumption to understand the tradeoff between safety margin and required portfolio size.
Checking progress toward an existing FIRE goal: Recalculate periodically with updated savings and expense figures to check actual progress against a previously set financial independence target.
Planning for a partial or "Coast FIRE" milestone: Use the calculator's growth projection to estimate when current savings alone, without further contributions, might grow to a target number.
Understanding how expense changes affect the FIRE target: Adjust the annual expense figure to see how a lower or higher cost of living in retirement shifts the calculated FIRE number significantly.

About This Tool

What is it? A browser-based tool that calculates a Financial Independence number and estimated timeline based on expenses, withdrawal rate, savings, and growth assumptions, without uploading any financial data to a server. Results are informational estimates, not financial advice.

Why use it? It turns the abstract goal of financial independence into a concrete target number and timeline, letting you test how different savings rates and assumptions change the outcome.

Alternatives: A financial advisor can provide a more personalized retirement projection accounting for tax situations and other individual factors; spreadsheet-based FIRE calculators exist but require manual formula setup; this tool gives an instant, adjustable projection without any spreadsheet work.

Common mistakes: Underestimating annual expenses, especially by excluding irregular costs like irregular large purchases or healthcare, produces an artificially low and overly optimistic FIRE number; the second is assuming an overly optimistic investment growth rate, which understates how long reaching the target might actually take in a more typical or conservative market environment.

Frequently Asked Questions

Is my financial data uploaded to a server?: No, the calculation happens entirely in your browser using JavaScript; nothing is transmitted or stored anywhere.
What is a safe withdrawal rate, and why does it matter so much?: It's the percentage of your portfolio you plan to withdraw annually in retirement; it matters because it directly determines how large a portfolio you need relative to your spending, with lower rates requiring proportionally larger portfolios.
Why does the commonly cited 4% rule imply a number of 25 times expenses?: Mathematically, withdrawing 4% annually means the portfolio is 25 times the annual withdrawal amount, since 1 divided by 0.04 equals 25.
Is the 4% withdrawal rate guaranteed to be safe?: No, it's based on historical market analysis over specific past periods and isn't a guarantee for any individual's future retirement, which is why some practitioners choose a more conservative rate for additional safety margin.
How does this differ from a standard retirement calculator?: Standard retirement calculators often assume a traditional retirement age around 65; FIRE calculations are typically used for much earlier, self-directed retirement timelines based on hitting a specific portfolio target rather than a specific age.
Should I include Social Security or pension income in this calculation?: This tool focuses on the core FIRE number derived purely from your invested portfolio and expenses; if you expect other income sources, you may want to factor those in separately when interpreting the result.
How often should I recalculate my FIRE number?: Recalculating periodically, such as annually or whenever expenses or savings change meaningfully, keeps the target and timeline aligned with your actual current financial situation.
Does this account for inflation?: The growth rate and expense figures you enter should ideally already reflect your own assumptions about inflation, since the calculation itself doesn't separately model inflation unless you build it into those inputs.

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