Practical guide
Understanding retirement withdrawal planner — target retirement portfolio
Everyday editorial team · GEOINNOVATION CO., LTD · Published · Updated
What this calculation is for
A retirement drawdown projection explores whether a chosen spending pattern can fit a portfolio over a selected horizon. The distinction between a fixed percentage of the remaining fund and an inflation-adjusted dollar withdrawal is important: they produce different spending paths.
How the method works
This model takes a first-year amount equal to the initial portfolio times the withdrawal rate. That dollar amount grows by the inflation assumption each year. Withdrawals occur at the start of the year, are capped by available assets, and the remainder earns the assumed return after fees.
A worked example
A $500,000 starting balance at 4% gives a $20,000 first-year draw. With 3% inflation, the requested second-year draw is $20,600, not simply 4% of whatever the balance becomes.
Assumptions and real-world differences
A constant return cannot represent sequence risk or market crashes. Taxes, benefit income and changing care expenses are excluded. If assets deplete, requested future spending is not magically funded; the model caps withdrawals to what remains.
Solving for retirement portfolio
This reverse calculation searches for a retirement portfolio that makes the model’s headline measure approach your target. Set a lower and upper search bound, leave the other assumptions consistent, and inspect the achieved result and target difference. The returned number is an input, not the original model’s output. A bounded solution can be approximate when the allowed input step rounds values.
Reproduce this tool’s example
These fixed example inputs are independent of edits you make above. Enter them in this tool to reproduce the result, then replace them with your own assumptions.
- Target: first-year withdrawal
- 30,000 $
- Minimum retirement portfolio
- 375,000 $
- Maximum retirement portfolio
- 1,125,000 $
- Initial annual withdrawal rate
- 4 %
- Annual inflation adjustment
- 2.5 %
- Years in retirement
- 30 years
- Assumed annual return
- 4 %
- Annual portfolio fees
- 0.3 %
Required retirement portfolio: $750,000
Closest modeled result: $30,000.
- Target headline value: 30,000
- Calculated headline value: $30,000
- Absolute target difference: 0
Frequently asked questions
- Is this a safe-withdrawal test?
- No. It is a deterministic scenario, not a probability or guarantee of success.
- Does it include Social Security?
- Not in this portfolio-only projection unless another tool explicitly provides that income input.
- Why might there be no exact required retirement portfolio?
- The target may be outside the search range. Rounded outputs, whole-item counts, tax thresholds and flat responses can also prevent an exact solution. Bisection requires a monotonic response within the chosen range; do not interpret a failed search as a real-world impossibility.