What is Coast FIRE?
Coast FIRE means you've saved enough that, with no further contributions, investment growth alone will carry your portfolio to your full FIRE number by retirement. After that you only need to earn enough to cover current spending — which is where the optionality comes from.
One person or a couple
Start with just you — one age, one set of accounts, one Social Security benefit. Planning with a partner? Add them to track two ages, two retirement dates, separate 401(k)s, IRAs, Roths and HSAs, and different employer matches. Each person can retire and claim Social Security at their own age.
How the numbers work
FIRE number = annual spending ÷ withdrawal rate, grossed up so your cash reserve sits on top. Coast number = FIRE number ÷ (1 + blended real return)years to retirement. Social Security lowers the long-run target to (spending − benefits) ÷ withdrawal rate, but the portfolio also has to bridge every year between retirement and your claiming age — or each partner’s, if you’re planning together. If your invested total is above the Coast number, you've coasted. Otherwise we project your contributions forward year by year to find the first year you could stop.
FAQ
Is 4% or 5% the right withdrawal rate?
4% comes from historical studies of 30-year retirements; early retirees with 40+ year horizons often use 3.25–3.75%. 5% is aggressive. Try several.
What real return should I use?
A diversified stock-heavy portfolio has historically returned roughly 5–7% real, but the future may differ. The 3%/5%/7% scenarios show how sensitive your plan is.
How does staggered retirement work here?
When you add a partner, each person stops contributing at their own retirement age. Until the last person retires, we assume the working partner's paycheck covers spending, plus any yearly portfolio withdrawals you enter. Your FIRE target is the balance needed on the day the last person retires.
How is Social Security handled?
Enter your estimated annual benefit in today's dollars (from ssa.gov) and claiming age (62–70). If you’re planning with a partner, enter both. Once benefits start, the portfolio only needs to cover spending minus benefits. Before each claim, the portfolio covers the missing benefit — we add the present value of those bridge years to your FIRE number. Use the haircut input (20–25% is a common cushion) if you're worried about future cuts. Spousal and survivor benefits aren't modeled.
Does this include taxes?
Not yet. Pre-tax balances will owe income tax on withdrawal; build that into your spending number. A Roth ladder and tax-aware withdrawal tool is coming.
What does the range of outcomes mean?
We run 1,000 simulated return paths (normally distributed annual real returns, 15% volatility) on the stop-contributing scenario. It is a simplified model, not historical backtesting.
Is my data saved?
Your numbers are saved only in this browser, and also in the page URL so you can bookmark or share a scenario. Nothing is sent to a server. Start over on the form clears what this browser saved for this calculator.