CoastFI (Coast Financial Independence) is the milestone where your invested savings will grow to a full retirement nest egg without any further contributions. Calculate your CoastFI number below.
CoastFI — also written as Coast FI or Coast FIRE — is a financial independence milestone. You've reached CoastFI when your invested portfolio is large enough that, with average market returns and no further contributions, it will grow into a full retirement nest egg by your target retirement age. You still need to work to cover current expenses, but you no longer need to save for retirement.
CoastFI Number = (Annual Expenses ÷ Safe Withdrawal Rate) ÷ (1 + Real Return)Years to Retirement
A 30-year-old who needs $50,000/year in retirement at age 65 has a full FI number of $1,250,000 (assuming 4% withdrawal). At a 7% real return over 35 years, they only need about $117,000 invested today to coast to that target — that's their CoastFI number.
CoastFI: Stop saving. Investments grow into full FIRE on their own.
Barista FI: Partial FI. Investments cover most expenses, part-time job covers the rest.
Lean FI: Full FI on a frugal budget under $40K/year.
Fat FI: Full FI with a generous $100K+/year budget.
Yes — CoastFI, Coast FI, and Coast FIRE all refer to the same concept. Some people prefer "CoastFI" because not everyone wants to "retire early" — they just want the financial independence and the freedom to choose.
Most planners use a 5–7% real return (after inflation). The S&P 500 has historically returned about 7% real over long periods, but past performance doesn't guarantee future results. Conservative planners use 5% to build in a margin of safety.
This is the main risk. If you stop contributing and markets underperform for an extended period, you may need to resume saving or push your retirement date back. Many CoastFI achievers continue contributing small amounts as insurance, even after technically hitting the number.
No. CoastFI just means you don't need to save for retirement anymore — you still need income to cover today's living expenses. Full retirement requires either Barista FI (partial work covers expenses) or full FI (portfolio covers everything).
Regular retirement planning assumes you keep contributing every year until retirement. CoastFI flips that — you front-load enough that compound growth alone gets you there. The earlier you hit CoastFI, the more time compound interest has to work, and the less total dollars you need to invest.