Compound Interest & Early Retirement Visualizer
Project when your investment income will cover your living expenses. Adjust savings rate, returns, age, and spending with live graph updates.
Find out when your investments can replace your salary
Most people know they should save for retirement, but very few can answer the actual question: "How many years until my portfolio generates enough passive income to cover my living expenses?" This calculator answers that directly. Enter your current age, savings, monthly contribution, expected annual return, monthly expenses in retirement, and safe withdrawal rate β and the tool shows you the exact age at which your passive income crosses your expense threshold, plotted on an interactive chart with a clear crossover marker.
The chart displays two lines: your growing portfolio balance (in purple) and the monthly passive income it generates (in green). A dashed yellow line marks your monthly expenses. Where the green line crosses above the yellow line is your FIRE date β the point at which work becomes optional. Drag any slider and the entire chart recalculates instantly, so you can compare scenarios in seconds.
Who uses this calculator
With $25,000 in savings and a $1,000 monthly contribution at 7% real return, the tool shows a FIRE age of approximately 55 β meaning 25 years of aggressive saving. Increasing the contribution to $1,500/month pushes that to age 49. The visual comparison makes the trade-off between savings rate and time immediately obvious.
Partners earning $90,000 and $75,000 can enter their combined $3,500 monthly contribution and shared $5,000/month retirement expenses. Running both a conservative 5% and moderate 7% return scenario gives a planning range β FIRE at 52 under optimistic assumptions, 57 under conservative ones.
A 45-year-old with $400,000 in superannuation considering a voluntary redundancy can test whether their existing balance plus reduced contributions covers expenses until preservation age. The tool shows whether the numbers work or whether additional private savings are needed.
Adjusting the safe withdrawal rate from 4% to 3.5% shows how a more conservative approach delays FIRE by 3-5 years but provides a wider margin of safety against market downturns β a key consideration for anyone retiring before 50 with 40+ years of portfolio drawdown ahead.
How the FIRE projection is calculated
The calculator projects your portfolio forward year by year using two compounding formulas running in parallel: one for your existing savings and one for your recurring monthly contributions. At each year, it checks whether the portfolio's passive income β calculated as portfolio balance multiplied by the safe withdrawal rate, divided by 12 β meets or exceeds your stated monthly expenses. The first year where this condition holds is your FIRE crossover point.
All calculations run locally in your browser. No financial data you enter is stored or transmitted.
The two-component formula
Portfolio(t) = S Γ (1 + r/12)^(12t)
+ C Γ [((1 + r/12)^(12t) β 1) / (r/12)]
Monthly Passive Income(t) = Portfolio(t) Γ SWR / 12
FIRE crossover when: MonthlyPassiveIncome(t) β₯ MonthlyExpensesThe first term, S Γ (1 + r/12)^(12t), compounds your current savings monthly. If you start with $50,000 and earn 7% annually, after 1 year that's $50,000 Γ (1 + 0.07/12)^12 = $53,632. After 10 years, it's $100,767 β your initial savings doubled without adding a single extra dollar, purely from compound growth.
The second term, C Γ [((1 + r/12)^(12t) β 1) / (r/12)], accumulates your monthly contributions with compound growth. Each $1,000 deposit earns returns for every remaining month until the projection endpoint. After 10 years of $1,000/month contributions at 7%, you've deposited $120,000 but the balance is $173,043 β the extra $53,043 is compound growth working on your regular deposits. This is why starting early matters so much: a 25-year-old contributing $1,000/month for 30 years at 7% ends up with $1,219,971, while a 35-year-old doing the same for 20 years ends up with $518,088 β less than half, despite contributing 67% as much money.
The safe withdrawal rate and why it matters
The safe withdrawal rate (SWR) determines what percentage of your portfolio you can withdraw each year without running out of money. The most widely cited benchmark is the 4% rule, derived from the 1998 Trinity Study by Cooley, Hubbard, and Walz. That study examined rolling 30-year periods in US market history and found that a portfolio invested in 50-75% stocks and 25-50% bonds sustained a 4% annual withdrawal rate in 95% of observed periods. For early retirees with 40-50 year horizons, the research is less encouraging: many financial planners now recommend 3-3.5% to provide a sufficient margin of safety against prolonged bear markets or higher-than-expected inflation.
In this tool, the SWR slider defaults to 4%. At that rate, a $1,000,000 portfolio generates $40,000/year in passive income, or $3,333/month. Drop the SWR to 3% and that same portfolio generates $2,500/month β meaning you need $1,333,333 to achieve the same $4,000/month income target. The FIRE age shifts accordingly.
Monthly compounding and why it's the standard
The model compounds at monthly intervals (r/12 per month, 12t total periods), which is the standard convention for retirement projections. This matches how most index funds, superannuation accounts, and managed portfolios report returns. Annual compounding would slightly overstate growth because it ignores the intra-year reinvestment of returns. The difference is small for low-contribution portfolios but becomes material for high-contribution scenarios β for example, contributing $3,000/month at 7% over 30 years produces $3,659,914 with monthly compounding versus $3,590,690 with annual compounding, a $69,224 difference.
When FIRE isn't achievable
If your monthly expenses are too high relative to your savings rate and return assumptions, the passive income line never crosses the expense threshold before age 80. The tool displays a warning message suggesting you increase contributions or adjust expectations. This is not a failure of the calculator β it's an honest output that reflects a real planning constraint. In practice, the most common levers are increasing the monthly contribution, extending the working years, reducing expected retirement expenses, or accepting a higher withdrawal rate with its accompanying risk.
Frequently Asked Questions
What is FIRE?
FIRE stands for Financial Independence, Retire Early. It describes the point at which your invested assets generate enough passive income to cover living expenses indefinitely, freeing you from the need to work for money. The concept originated in the 1990s with Vicki Robin and Joe Dominguez's book "Your Money or Your Life" and has since grown into a global movement. The core idea is simple: save aggressively (typically 50-70% of income), invest in low-cost index funds, and reach the crossover point where your portfolio's annual return exceeds your annual spending. The calculator on this page models that crossover point using the standard future-value formula.
What is the 4% rule?
The 4% rule originates from the 1998 Trinity Study by Cooley, Hubbard, and Walz, which examined rolling 30-year periods in US market history from 1926-1976. They found that a portfolio of 50-75% stocks and 25-50% bonds sustained a 4% annual withdrawal rate (adjusted for inflation) in 95% of observed periods. The rule means a $1,000,000 portfolio can safely generate $40,000/year in inflation-adjusted income. However, the Trinity Study was designed around a conventional 30-year retirement. For early retirees with 40-50 year horizons, the success rate drops, and many financial researchers now recommend 3-3.5% instead.
Is a 7% annual return realistic?
The US stock market (S&P 500) has returned roughly 10% annually before inflation and approximately 7% after inflation over the past century. 7% is the standard real return estimate used by financial planners for a diversified equity portfolio. Your actual returns will vary dramatically year to year β the S&P 500 returned +26% in 2023 and -18% in 2022. Over any 10-year period, returns have ranged from -2% to +20% annualised. International markets may perform differently, and past performance does not guarantee future results. The calculator lets you adjust the return rate to test conservative (5%) and optimistic (9%) scenarios.
Does this account for inflation?
Not separately. The tool uses a single return rate, so you should enter a real (inflation-adjusted) return rather than a nominal one. For example, if stocks return 10% nominally and inflation is 3%, use 7% as your return rate and enter your expenses in today's dollars. This produces a conservative, inflation-adjusted FIRE estimate. Alternatively, you can use the nominal return (10%) and inflate your expense figure by your expected inflation rate β but this approach is less intuitive because the crossover point is expressed in future dollars, not today's purchasing power.
How do I factor in superannuation or government pension?
Reduce your monthly expenses by the expected monthly pension or super drawdown. If you need $4,000/month total and expect $1,000/month from Australian superannuation, enter $3,000 as your monthly expenses β the gap your personal portfolio needs to cover. Note that Australian super has a preservation age (currently 60 for those born after 1 July 1964) and contribution caps ($30,000/year for concessional contributions in 2024-25). If you plan to retire before 60, you'll need enough private savings to bridge the gap until super becomes accessible.
What if I plan to increase contributions over time?
This tool models a fixed monthly contribution. To approximate stepped increases, run the calculation twice: first with your current contribution to estimate your portfolio at a mid-point age, then re-run using that portfolio value as starting savings with the higher contribution rate. For example, if you currently save $1,000/month and plan to increase to $2,000/month in 5 years, run the tool at $1,000/month to age 35, note the portfolio value, then re-run from age 35 with $2,000/month. This staged approach gives a reasonable upper-bound estimate of the impact.
How does tax on investment returns affect my FIRE timeline?
This calculator does not model tax on capital gains or dividends. In practice, the tax impact depends on your account structure. In Australia, superannuation earnings are taxed at 15% (accumulation phase) or 0% (retirement phase after 60). In a personal brokerage account, capital gains tax applies when you sell β 50% discount applies for assets held over 12 months. To approximate the impact, use a lower return rate: 5% instead of 7% if you expect significant tax drag. Alternatively, maximise tax-advantaged accounts first to shelter returns.
What withdrawal rate is safe for a 40+ year retirement?
The original Trinity Study was designed around a 30-year retirement horizon and found 4% had a 95% success rate. For early retirees with 40-50 year horizons, the research is more nuanced. The ERN (Early Retirement Now) Safe Withdrawal Rate series, which analysed 160+ years of US data, suggests 3.25-3.5% for a 50-year retirement with a 95%+ success rate. You can test this directly in the tool by adjusting the SWR slider: dropping from 4% to 3.5% typically delays FIRE by 3-5 years but significantly reduces the probability of running out of money.
Should I pay off my mortgage before investing for retirement?
This depends on your mortgage rate versus your expected investment return. If your mortgage is at 5% and you expect 7% real returns from index funds, investing the extra money generally produces a better long-term outcome β but with more volatility. Paying off the mortgage gives a guaranteed 5% "return" in the form of avoided interest, which is risk-free. Many FIRE practitioners split the difference: contribute enough to retirement accounts to get employer matches (which are guaranteed 100% returns in Australia via the Superannuation Guarantee), then direct surplus cash to the higher-interest debt.