Read the Retirement Projection as a Scenario
The calculator compounds the return and contribution assumptions you enter to project a future balance, with an inflation-adjusted view where applicable.
A withdrawal amount based on 4% is shown only as an illustrative rule-of-thumb scenario. Portfolio longevity depends on market returns, inflation, taxes, fees, spending changes and withdrawal timing, so no success probability is guaranteed by this tool.
Retirement projections are most useful as a range, not as a promise about a future account balance. Returns rarely arrive smoothly, inflation changes over time, and contributions can rise or fall with income. Try a cautious return assumption, a middle case and a stronger case, then look at how sensitive the result is. If a small change in the assumed return produces a very different outcome, that tells you the plan depends heavily on market performance and may benefit from higher contributions or more flexibility around retirement timing.
Frequently Asked Questions
Does the 4% figure guarantee that my portfolio lasts 30 years?
No. It is a planning heuristic, not a guarantee or probability claim for your situation.
Should I use one expected return for my retirement plan?
It is better to test several plausible rates. A single long-term average hides volatility and can make a projection look more certain than it really is.
Methodology & Related Tools
Review how RatioCalc builds, tests and updates calculator models before using an estimate for a material decision.
Accuracy review
Investing & Savings family audit: .
Site-wide consistency review: September 4, 2026.