Coast FIRE Calculator
Find out when you can stop saving for retirement and let compounding finish the job. You still work to cover today's expenses, but no more retirement contributions are required.
See your real Coast FIRE progress, updated automatically.
Connect your retirement accounts and watch your number compound month over month.
What is Coast FIRE?
Coast FIRE is the milestone where your existing retirement portfolio, left completely alone, will compound to your full FIRE number by traditional retirement age. It is the first major FIRE checkpoint and arguably the most underrated. You still need to cover today's expenses through work, but the long-term retirement question is solved. The pressure to keep saving disappears. From here, the snowball rolls itself.
The math behind Coast FIRE
The formula is straightforward:
Coast FIRE = FIRE Number / (1 + r)^n
Where r is the expected real annual return and n is the number of years until retirement. The full FIRE number is your annual retirement spending divided by your withdrawal rate (typically 4%, giving you 25 times annual spending). The Coast FIRE number is that target discounted back to today by the compounding effect of those remaining years.
Why Coast FIRE happens so much earlier than FIRE
The further you are from retirement, the more compounding does the work for you. A 25 year old aiming to retire at 65 has 40 years of compounding ahead. At 7% real returns, $1 invested today becomes nearly $15 at retirement. That means their Coast FIRE number is roughly 7% of the full FIRE target. For a $1 million FIRE goal, Coast FIRE arrives at around $67,000 invested. The same person at 45 has only 20 years left, and Coast FIRE shifts to $258,000. The lesson: time horizon is the most powerful variable in the entire equation. Saving aggressively early in your career produces an outsized payoff.
Coast FIRE vs FIRE vs Barista FIRE
The FIRE community has several milestones, each representing a different relationship with work and money:
- Coast FIRE: your portfolio is large enough to compound to your retirement target without further contributions. You still work to cover today's expenses, but you no longer need to save for retirement.
- Barista FIRE: your portfolio is large enough that a part-time or flexible job, combined with modest withdrawals, covers your lifestyle. You step away from full-time work but maintain some income.
- Full FIRE: your portfolio supports your full lifestyle through withdrawals indefinitely. No more work required.
How to use Coast FIRE in practice
Coast FIRE is best treated as a permission slip, not a finish line:
- Take a sabbatical or career break without derailing retirement.
- Switch to a lower-paying job you find more meaningful, knowing your retirement is already funded.
- Start a business that requires reinvesting most of your earnings for a few years.
- Move to a lower cost of living area and accept the pay cut.
- Reduce hours, work seasonally, or freelance instead of grinding full time.
The psychological shift is the real benefit. The grind of saving for retirement disappears, and you can make decisions about work based on what you actually want, not what your future self requires.
Fixed rate vs. historical cycles
The fixed rate mode projects your portfolio forward at a single assumed real return. It is fast, simple, and useful for a back-of-the-envelope view of when you cross Coast FIRE and FIRE.
The historical cycles mode replays your plan across every rolling N-year period in US market history (back to 1926), where N is your years to retirement. It tests whether your current portfolio plus continued savings would actually have reached the FIRE number by retirement age across all of those historical sequences. The success rate is the share of cohorts whose portfolio crossed FIRE in time. A high success rate means your plan is robust to the kind of market sequences that have actually happened, not just to your average return assumption. This matters especially for Coast FIRE, because the moment you stop contributing your portfolio depends entirely on returns, and sequence-of-returns risk has more leverage on the outcome.
Picking a return assumption
The default of 7% real return reflects the long-run inflation-adjusted return of the US stock market (roughly 10% nominal minus 3% inflation). It is a reasonable assumption for a stock-heavy portfolio held over decades, but it is not guaranteed. Conservative planners use 5%, which adds a healthy margin of safety. Be aware: a 2 percentage point swing changes your Coast FIRE number dramatically. At 30 years out, 7% returns require a $131,000 starting portfolio for a $1 million target; 5% returns require $231,000 for the same target. The longer your horizon, the more the assumption matters.
Should you actually stop saving after Coast FIRE?
Most people who hit Coast FIRE keep saving, and you probably should too. The reasons are practical. Continued contributions move your full FIRE date earlier, build a margin against bad market returns, fund a higher retirement lifestyle, or simply preserve optionality. Coast FIRE is best read as "you no longer have to save," not "you must stop." The freedom is in having the choice.
Frequently asked questions
What is Coast FIRE?
Coast FIRE is the portfolio size today which, left untouched and compounding at the assumed real return, will grow to your full FIRE number by your target retirement age. Once you hit Coast FIRE, you no longer need to save another dollar for retirement. You still need to cover today's living expenses through work or other income, but the retirement question is solved.
How do you calculate Coast FIRE?
Start with your full FIRE number (annual retirement spending divided by your withdrawal rate, typically 4%). Then discount that target back to today using the formula: Coast FIRE = FIRE Number / (1 + r)^n, where r is the expected real return rate and n is the years until retirement. For example, if your FIRE number is $1 million, you assume 7% real returns, and you have 30 years until retirement, your Coast FIRE number is roughly $131,000.
What is the difference between Coast FIRE and Barista FIRE?
Both involve stepping back from full-time work before traditional retirement. Coast FIRE means you stop contributing to retirement but still cover your living expenses through full-time work. Barista FIRE means you draw down a smaller portfolio while supplementing with part-time or flexible work. Coast FIRE is generally the earlier milestone because the portfolio target is smaller (it just needs to compound, not support you yet).
Why does Coast FIRE work?
Compound growth. Once a portfolio is large enough, the returns it generates each year are bigger than any savings contribution you could realistically make. From that point on, the snowball rolls itself. A $130,000 portfolio earning 7% real for 30 years becomes roughly $990,000 with zero new contributions. The math is the same as if you had saved aggressively for the whole 30 years, except you front-loaded the work into the first decade of your career.
What return rate should I assume?
Most Coast FIRE calculators default to 7% real returns (after inflation) for stock-heavy portfolios, based on the long-run historical return of the US stock market. More conservative planners use 5%. The choice matters: assuming 7% versus 5% can shift your Coast FIRE number by 50% or more over a 30-year horizon. The longer your horizon, the more compounding amplifies the difference.
How is the withdrawal rate connected to Coast FIRE?
The withdrawal rate sets your full FIRE number, which in turn sets your Coast FIRE target. A 4% withdrawal rate (the standard FIRE assumption from the Trinity Study) means your FIRE number is 25 times your annual spending. A more conservative 3.5% rate sets it at roughly 29 times. Early retirees who plan for 50+ year retirements often drop to 3 to 3.5% because of sequence-of-returns risk. Use whatever rate matches your risk tolerance and time horizon.
Should I stop investing once I hit Coast FIRE?
Most people who hit Coast FIRE choose not to stop. The mental relief is the main benefit: you have removed the pressure to save. But continued contributions accelerate the math, give you a margin against bad market returns, and create optionality (earlier retirement, more spending in retirement, generational wealth). Coast FIRE is best framed as 'you no longer have to save', not 'you must stop saving'.