Coast FIRE Calculator – When Can You Stop Saving?

Coast FIRE (Coast Financial Independence, Retire Early) is the point at which your existing investments have grown enough that—even if you stop contributing entirely—they will compound and reach your full retirement target by your desired retirement age. In other words, you've already done the heavy lifting; now you just need to let time and compound interest do the rest. You can "coast" by taking a lower-paying but more fulfilling job, reducing hours, or simply spending more of your paycheck.

Traditional FIRE (Financial Independence, Retire Early) means you have enough savings to retire immediately and cover all expenses indefinitely. Coast FIRE is a milestone along the journey—you haven't saved enough to retire today, but you've saved enough that your money will grow to your FIRE number by your target retirement age without any additional contributions. It offers psychological freedom: you can scale back on work or spending without derailing your retirement.

The 4% Rule, popularized by the Trinity Study, states that you can safely withdraw 4% of your retirement portfolio in the first year (adjusted for inflation thereafter) with a high probability of not running out of money over a 30-year retirement. For Coast FIRE calculations, this rule determines your target retirement number: simply multiply your expected annual retirement expenses by 25 (since 1 ÷ 0.04 = 25). For example, if you need $50,000/year in retirement, your FIRE target is $1,250,000. Some prefer a more conservative 3.5% (28.5×) or 3% (33.3×) withdrawal rate.

Inflation erodes purchasing power over time. Our calculator uses the real rate of return (nominal return minus inflation) to project your savings growth in today's dollars. For instance, if you expect 7% nominal returns and 3% inflation, your real return is approximately 4%. This means your Coast FIRE target will be higher because your money needs to grow more to outpace inflation. Tip: Always think in today's dollars when planning retirement expenses—it makes the numbers more tangible and realistic.

Yes, typically. Coast FIRE means you still need to cover your current living expenses through active income—you just don't need to save additional money for retirement. Many people use Coast FIRE as an opportunity to switch to a less stressful or more meaningful career (sometimes called "Barista FIRE"), work part-time, freelance, or pursue passion projects that generate some income. The key freedom is that your retirement is already funded; you just need to "coast" to cover day-to-day expenses until retirement age.

Your Coast FIRE number depends on three main factors: (1) your target retirement amount (annual expenses × 25 based on the 4% rule), (2) your expected rate of return, and (3) the number of years until retirement. The longer the time horizon, the smaller your Coast FIRE number because compound interest does more of the work. For example, with a $1.25M target and 7% returns, you need ~$117K at age 30 (35 years to grow), but ~$635K at age 55 (only 10 years to grow). Start early—time is your biggest ally.

This calculator uses several standard assumptions: (1) Constant annual real rate of return (nominal return minus inflation), (2) The 4% safe withdrawal rule (or your chosen SWR) to determine the retirement target, (3) Retirement expenses stay constant in today's dollars, (4) Compound interest is calculated annually, and (5) No taxes or fees are factored in (use a tax-advantaged account like a 401(k) or IRA in practice). These are simplifications—real markets fluctuate, so consider this a guideline rather than a guarantee. We recommend running the numbers with conservative return estimates.

If you continue saving beyond your Coast FIRE point, you'll reach full FIRE sooner than your original target retirement age, or you'll retire with a larger nest egg that provides more security and flexibility. The chart on this page illustrates both paths: the "Keep Saving" line shows the accelerated trajectory if you maintain contributions, while the "Coast Path" shows the baseline where you stop saving. Continuing to save is always financially beneficial—Coast FIRE simply gives you the option to ease off the gas pedal if you choose.

Yes, Coast FIRE carries market risk. If returns are lower than projected, your savings may not grow enough by retirement. To mitigate this: (1) Use conservative return estimates (e.g., 5-6% real return instead of 7-8%), (2) Diversify your investments broadly (low-cost index funds), (3) Consider a lower safe withdrawal rate (3.5% or 3%), (4) Build in a margin of safety by targeting 110-120% of your calculated Coast FIRE number, and (5) Stay flexible—if the market dips, you can always resume saving. Coast FIRE is a milestone, not a binding contract.