Current Plan vs Saved Plan
Portfolio and withdrawals over time
Year by year
| Year | Age | Savings / year | Portfolio value | Monthly withdrawal |
|---|
When you hit the levels
| Withdrawal / mo | Required portfolio | Year | Age |
|---|
How To Use The Calculator
Use this page as a decision tool, not a prediction machine. The real value is seeing how your current plan behaves when you change one assumption at a time.
- Enter your starting balance: the amount you already have invested today.
- Add your monthly contribution: the amount you expect to invest each month from now on.
- Choose an annual return assumption. Use a conservative long-term estimate rather than a best-case market year.
- Set annual savings growth if you expect your monthly investing to rise over time with income growth or lifestyle changes.
- Enter your current age so the calculator can translate years into an estimated FIRE age.
- Add your expected monthly expenses in retirement, including a buffer for irregular costs.
- Choose a withdrawal rate. Many FIRE plans start around 4%, but a lower rate may be more conservative for long retirements.
- Review the output, then change one assumption at a time to see which inputs matter most.
Method And Assumptions
The calculator first converts spending into a portfolio target by annualizing monthly expenses and dividing by the withdrawal rate. It then projects your portfolio forward with growth, ongoing contributions, and optional contribution growth until the plan crosses that target.
That straight-line approach is useful for planning, but it is still a simplification. It does not model taxes, fees, pension rules, one-time shocks, or the order in which returns arrive. Real markets do not deliver the same return every year, which is exactly why pages like the Monte Carlo FIRE Simulator and Historical FIRE Backtest exist.
If your return assumption is a real return after inflation, keep expenses in today’s money. If your return is nominal, remember that future spending usually rises too. This is not financial advice. It is a structured way to compare scenarios and spot where a plan is thin.
Real Example
Imagine a 32-year-old investor with 500,000 already invested, adding 8,000 per month, and increasing contributions by 2% each year. They expect a 5% annual real return and want to spend 30,000 per month in retirement. With a 4% withdrawal rate, the required portfolio is about 9,000,000 because the annual spending target is 360,000 and 360,000 divided by 0.04 equals 9,000,000.
The estimated FIRE age is the first age where the projected portfolio reaches that required portfolio. If the result says the investor reaches FIRE around age 50, that does not mean retirement is guaranteed at 50. It means the assumptions entered create a path where the portfolio crosses the target around that age.
How To Interpret The Results
The required portfolio tells you the size of the target. FIRE age tells you when the current plan reaches it. Projected retirement income tells you what the end portfolio might support if the assumptions hold.
Read those numbers together. If the target looks manageable but the age is still far away, the issue is pace. If the age looks good only when returns are generous, the issue is fragility. If a small spending change moves the result by years, the issue is lifestyle sensitivity.
Common Mistakes And Misunderstandings
A common mistake is using an aggressive return assumption because it makes the FIRE age look better. Long-term equity returns can be strong, but the order of returns matters, and bad early retirement years can damage a withdrawal plan. Another mistake is entering current monthly expenses without adding retirement-specific costs such as health care, home repairs, or tax on withdrawals.
Many users also confuse a withdrawal rate with a guaranteed return. A 4% withdrawal rate does not mean the portfolio earns 4% every year, and it does not eliminate risk. For early retirement, flexible spending, cash reserves, part-time income, and lower withdrawal rates can all matter.
Limitations
This calculator is intentionally useful before it is exhaustive. It cannot know your future tax rate, health-care costs, housing shifts, family obligations, pension rules, or how flexible you would really be in a downturn.
For a stronger read, run conservative cases on purpose: lower returns, higher spending, lower withdrawal rates, and no contribution growth. If the plan still works there, the pleasant case becomes more believable.
FAQ
Is the 4% rule safe for early retirement?
The 4% rule is a useful starting point, but it is not a guarantee. Early retirees often plan for longer time horizons, so many prefer testing 3.5%, 3.25%, or 3% as a more conservative withdrawal assumption.
Should I use returns before or after inflation?
Use a consistent approach. If you enter an inflation-adjusted return, keep expenses in today's money. If you enter a nominal return, remember that future expenses will usually be higher because of inflation.
Does this include taxes?
No. Taxes depend on your country, account type, cost basis, pension rules, and withdrawal strategy. If taxes will be meaningful, add a spending buffer or run a separate tax estimate.
What if my portfolio already reaches the target?
If the calculator shows you already meet the target, treat that as a reason to review the assumptions carefully. Check whether your spending estimate is complete, your withdrawal rate is appropriate, and your tax and health-care costs are included.
Where To Go Next
If you want to improve the main behavioral lever first, go to the Savings Rate Calculator. If you want to know whether the portfolio could eventually carry itself with less new money, open Coast FIRE. If you want to challenge this straight-line plan under rougher conditions, move next to the Monte Carlo FIRE Simulator or Historical Backtest. If you only need the spending target in isolation, the 4% Rule Calculator is the fastest baseline.