Coast FIRE questions, answered
Plain-English answers to the assumptions people most often overlook.
Does Coast FIRE mean I can retire now?
No. It means the invested balance may be able to reach a future retirement target without new contributions. Income is still needed to pay current expenses until withdrawals begin.
Should I use a 4% withdrawal rate?
Four percent is a common starting assumption, not a guarantee. Retirement length, investment mix, fees, taxes, spending flexibility, and future market returns all matter. Test lower rates such as 3% or 3.5% when you want a larger cushion.
What return should I enter?
Use an annual real return, after inflation and ideally after investment costs. Do not enter a nominal market return while also expressing spending in today’s dollars. Try more than one rate rather than treating a long-term average as certain.
Do I include a 401(k), IRA, or HSA?
Include assets intended and available for retirement, while remembering that taxes, access rules, and qualified medical use differ. The calculator treats every dollar alike; a detailed plan should not.
How should Social Security or a pension be handled?
Subtract the reliable annual income you expect those sources to cover from retirement spending, then enter the remainder as portfolio-funded spending. Use conservative benefit estimates and consider timing and survivor rules.
Why did my coast number rise after waiting a year?
There is one less year for compounding. The coast number can also rise when expected spending increases, the withdrawal rate falls, or the assumed real return falls.
What if I have already reached the number?
It means the inputs produce a mathematical surplus. Before reducing contributions, test adverse scenarios and account for taxes, healthcare, fees, irregular spending, and goals beyond basic retirement.