What does Coast FIRE mean here?
It is a checkpoint, not a retirement date. A Kitces article describes Coast FIRE as the point where retirement savings are projected to grow, without further contributions, into a portfolio that could support anticipated retirement spending, while work still covers ongoing living expenses. The same article treats the idea as a spectrum and notes that long horizons add uncertainty.
Kitces: Helping Clients Understand When They Have Enough Retirement Savings To Coast FIRE
Investopedia publishes the same present-value relationship: coast number equals the retirement goal divided by (1 + growth rate) raised to the years remaining. That article's worked example multiplies annual spending by 25, which is a 4% withdrawal convention, and it uses a 7% growth figure. Those are that article's illustrations. This calculator does not adopt them as recommended inputs. You type a real return and a withdrawal rate, and both are labeled as assumptions.
Investopedia: Reaching ‘Coast To FI’: The Path to Financial Freedom
Why can zero contributions fail to catch up?
Today's coast number is the retirement target discounted by the return you typed. With no new contributions, the projected portfolio and the coast threshold are multiplied by the same (1 + return) each year. If assets are short of today's coast number, they stay short, including when the return is zero or negative. The calculator then says: Not reached by your target retirement age under these assumptions. It does not fill in a year.
What is the retirement portfolio target?
It is annual retirement spend divided by the withdrawal rate you entered. Dividing by 4% is the same arithmetic as multiplying spend by 25. That arithmetic is not a finding that 4% will last for you.
Historical withdrawal studies describe past outcomes, not a promise about future returns. A withdrawal rate is a planning assumption that may need revisiting as markets and spending change.
Bogleheads wiki: Safe withdrawal rates
A November 2023 Journal of Financial Planning article describes William Bengen's 1994 study as examining 1926–1992 returns and finding a 4.0 percent maximum initial withdrawal for a 30-year span, for the portfolio and inflation-adjusted spending rules in that study. The article also says later research revisited that figure. This page does not rerun those studies and does not recommend a withdrawal rate. The 4.00% in the example form is only a placeholder.
Financial Planning Association: Revisiting William Bengen’s SAFEMAX Portfolio Withdrawal Rate
What is sequence-of-returns risk, and why is it missing?
Sequence-of-returns risk is the danger that poor returns early, together with money leaving the portfolio, do more damage than the same average in another order. A Kitces article argues that the research concern is the real returns over the early years of withdrawals, not only a single opening year.
Kitces: Understanding Sequence of Return Risk and Safe Withdrawal Rates
This model applies one return, identically, every year. It does not withdraw spending during the coasting years. A bad decade can leave a real portfolio short of the target even when this page shows a coast year.
Why does the page ask for a real return?
Amounts are in today's dollars, so the return should be what you assume is left after inflation. If you type a nominal return and also type spending in today's dollars, the two price levels are mixed.
Investor.gov's classroom page illustrates compound interest with a savings example: $100 earning 5% interest becomes $105 after one year and $110.25 after two, because the second year also credits interest on the first year's interest. That is a teaching example about compounding. It is not a forecast of investment markets, and it is not this calculator's assumption.
Investor.gov: What is compound interest?
Does already being at coast mean I can retire or stop paying bills?
No. It means that, under the fixed return you entered, new retirement contributions could stop and the invested balance could still meet the retirement portfolio target by the target age. Living expenses continue. You might still choose to keep contributing. This page does not know your job, debts, household, taxes, or health.
What does the model leave out?
Taxes, fees, and fund expenses, unless you already netted them out of the return you typed. Other income. Debts. The order of returns. How long you live. Changes in spending. Any currency other than USD. No investment product is named or recommended. Every estimate is an illustration under the assumptions on screen, not a guarantee.
Are the starting numbers advice?
No. Reset puts back age 35, retirement age 65, $80,000 invested, $40,000 of spending, $12,000 of contributions, 5.00% real return, and 4.00% withdrawal rate, and it clears the previous estimate. Replace every figure with your own hypothetical entries.
Is a longer retirement a reason to look again at a withdrawal rate?
The Bogleheads early-retirement page says withdrawal rates deserve another look when retirement is early, and it discusses spending that can adjust. This calculator divides by whatever rate you type inside its bounds. It does not choose a rate for a long life.