Coast FIRE
Stop saving for retirement without pushing back your finish line
Coast FIRE is the moment your current savings, left alone to compound, will grow into your full retirement number on their own. From there you only need to earn enough to cover today's expenses. Calculate your coast number free.
What Coast FIRE means
Regular FIRE asks you to save aggressively until your portfolio can cover every future expense, indefinitely. Coast FIRE is an earlier milestone: the point where your existing investments will reach your full FI target by retirement age through compound growth alone, no further contributions required.
Cross that line and the pressure to save disappears. You keep working if you want to, but the paycheck only needs to cover your current lifestyle, not fund your future one too.
The math behind your coast number
Coast FIRE Number = FI Target ÷ (1 + r)ⁿ
FI Target is the portfolio you want at retirement (often 25x your annual expenses under the 4% rule). r is your expected annual real return, usually 5-7%. n is the number of years left until retirement.
A 30-year-old with $100,000 invested, expecting a 7% return, aiming for $1,000,000 by age 60, has a coast number of $1,000,000 ÷ (1.07)^30, which works out to $131,367. Above that number today, the $1,000,000 target arrives on its own by 60.
Why geography changes your coast number
Geo-arbitrage, earning in a strong currency while living somewhere cheaper, can cut your path to Coast FIRE roughly in half. It works on both sides of the formula at once: it raises your savings rate during the years you are still accumulating, and it lowers the FI target itself once you plan to spend less long-term.
Picture the same $6,000 monthly income in two places. In San Francisco, $4,000 goes to expenses and $2,000 is saved. In Chiang Mai, the identical paycheck spends $1,500 and saves $4,500. At that savings rate the higher figure reaches its coast number in about half the time.
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Coast FIRE questions, answered
How much money do I need for Coast FIRE?
It depends on your age, target retirement age, expected returns, and how much you plan to spend in retirement. A 30-year-old targeting $1,000,000 at age 60 with a 7% return needs roughly $131,000 saved today. Use the calculator above for your own number.
What is the difference between Coast FIRE and regular FIRE?
Regular FIRE means saving until your portfolio covers all future living expenses indefinitely. Coast FIRE is the earlier point where your existing savings will grow to that same target through compound interest alone, so you only need to cover current expenses, not save anything additional.
Can I reach Coast FIRE faster with geo-arbitrage?
Yes. Living somewhere with a lower cost of living while earning the same income lets you save more aggressively in the years before you coast, which pulls your coast number closer. It also lowers your eventual FI target if you plan to keep living there.
What rate of return should I use in a Coast FIRE calculation?
Most financial planners use a 7% nominal return, roughly a 10% market return minus 3% inflation, for long-term stock investments. More conservative planners use 5-6%. Staying consistent matters more than picking the highest number you can find.
Is Coast FIRE safe? What are the risks?
The main risks are sequence-of-returns risk (a downturn early in your coasting years), inflation running higher than assumed, and unplanned costs like healthcare. Build in a margin of safety, keep an emergency fund, and re-check your number periodically.
What is the difference between Coast FIRE and Barista FIRE?
Coast FIRE is a savings threshold: once you pass it, you can stop saving entirely and just cover current costs. Barista FIRE assumes part-time work actively covers part of your spending gap, on top of a partial portfolio, rather than relying purely on compound growth.
Do I need to invest in stocks to reach Coast FIRE?
The formula only requires an expected real rate of return, it does not require stocks specifically. Most people use stock-market assumptions (5-7% real) because that is the most common long-term vehicle, but the same math works with any diversified investment you can reasonably project a return for.
Find your coast number
Enter your age, savings, and target to see exactly how close you are, and how location moves the finish line.