Coast FIRE Calculator
Coast FIRE Calculator
How much to invest now, then stop — and let compounding finish the job.
We Are Calculator
Professional Financial Tools
7/28/2026
Your age today
Age you plan to stop working entirely
401(k), IRA, brokerage accounts — not cash or home equity
Expected annual spending in retirement (today's dollars)
Total added to investments each year (including employer match)
Expected annual return already adjusted for inflation (historical S&P 500 real return ≈ 7%)
% of portfolio withdrawn per year in retirement. 4% is the standard from the Trinity Study.
Coast FIRE is the point at which your invested portfolio is large enough that — without adding another dollar — compound growth alone will carry it to your full FIRE number by your target retirement age. Once you hit your Coast FIRE number, you can stop saving for retirement entirely. You still need to earn enough to cover your current living expenses, but the future is funded.
The name captures the feeling: you've done the hard climbing, and now you can coast downhill to financial independence. Practically, Coast FIRE unlocks a menu of options that full FIRE doesn't offer until much later: shifting to less stressful work, going part-time, changing careers for meaning rather than income, or taking extended travel without worrying that you're falling behind on retirement savings.
The concept is part of the broader FIRE (Financial Independence, Retire Early) movement, which uses aggressive saving and index-fund investing to retire decades ahead of the traditional timeline. Unlike full FIRE — which requires accumulating 25× your annual spending before you can stop working — Coast FIRE is achievable with a much smaller portfolio, because time and compounding do the heavy lifting.
According to the SEC's Investor.gov compound interest calculator, even small differences in starting age dramatically affect how much you need to save. A 28-year-old targeting a $1.25 million retirement nest egg at 65 with a 7% real return needs a Coast FIRE number of roughly $97,000 — an amount many people can reach in their early 30s with consistent saving. A 40-year-old targeting the same goal needs $328,000. The decade costs $231,000 in required savings.
This calculator shows you three critical numbers: your full FIRE number (what you ultimately need), your Coast FIRE number (what you need invested today to coast from here), and how many years earlier Coast FIRE arrives versus grinding to full FIRE without stopping contributions. The chart visualizes both curves — your actual portfolio growth and the required "coast number" at each age — so you can see exactly when they intersect.
The Coast FIRE calculation uses two formulas in sequence. First, calculate your full FIRE number using the safe withdrawal rate (SWR). Then discount that target back to present value using the compound growth formula.
The 4% SWR comes from the Trinity Study (Cooley, Hubbard, Walz — 1998, updated 2011), which found that a 4% initial withdrawal rate, adjusted for inflation annually, sustained a diversified portfolio through 95%+ of historical 30-year periods. For longer retirements (40+ years), many planners use 3.5%.
This is the standard present value formula from finance — the same math used to value bonds and pension obligations. It answers: "How much money, invested today at the expected return, grows to the target by retirement?" The Federal Reserve uses analogous discounting in its monetary policy models.
The calculator defaults to 7%, which reflects the long-run inflation-adjusted S&P 500 return from 1926 through 2025, per Ibbotson/Morningstar historical data. This is already net of inflation — meaning all dollar figures stay in today's purchasing power without needing a separate inflation adjustment.
| Current Age | Years to Retire (65) | Coast FIRE Number | Full FIRE Number |
|---|---|---|---|
| 25 | 40 years | $68,000 | $1,250,000 |
| 30 | 35 years | $97,000 | $1,250,000 |
| 35 | 30 years | $164,000 | $1,250,000 |
| 40 | 25 years | $231,000 | $1,250,000 |
| 45 | 20 years | $328,000 | $1,250,000 |
| 50 | 15 years | $466,000 | $1,250,000 |
All figures are approximate, rounded to nearest $1,000. Formula: $1,250,000 ÷ (1.07)^n where n = years to retirement. Adjust your return assumption for conservative portfolios.
Enter your numbers and the calculator updates instantly — no button click needed. Here's what each input means and how to choose the right values:
The years between these two numbers is the compounding window — the most powerful variable in the formula. Changing your retirement age by 5 years can shift your Coast FIRE number by 30–40%.
Include 401(k), traditional IRA, Roth IRA, and taxable brokerage accounts. Do not include your primary home equity, savings accounts, or cash — only assets you expect to compound at your return assumption. If the result shows "Already Coasting," you've hit your number.
Use your expected annual spending in retirement in today's dollars — since you're using an inflation-adjusted real return, the calculator keeps everything in today's purchasing power. Most FIRE planners find retirement spending is lower than current spending (no mortgage payment after payoff, no commuting costs, Medicare at 65). The Budget Manager can help you model this precisely.
Total added to investment accounts each year including employer 401(k) match. This is used to project when your portfolio will cross the Coast FIRE number — after that intersection, the calculator stops counting contributions and lets compounding run unassisted.
The default 7% reflects the historical inflation-adjusted S&P 500 average. Use 5–6% for a conservative mix including bonds, or 5% if you're within 10 years of retirement. Run the calculator at both 5% and 7% to see your planning range.
4% is the standard from the Trinity Study. Use 3.5% if you plan a 40+ year retirement or want additional safety margin. Use 3.25% for a very early retirement (before 45). The Safe Withdrawal Rate Calculator models the historical success rate at any withdrawal percentage.
The calculator returns four outputs and an interactive chart. Here's how to read each:
Reading the chart: The "Your Portfolio" curve shows your actual portfolio growing with contributions, then continuing to grow (more slowly) without them after you coast. The "Coast Target" curve shows the required coast number at each age — it rises over time because as you get older, compound interest has fewer years to work, so you need more saved right now. Where the portfolio curve crosses the coast target: that's your Coast FIRE date.
Reaching Coast FIRE is a genuine inflection point, not just a milestone. Here's what it actually unlocks:
One critical caveat: Coast FIRE assumes your portfolio continues growing at the expected real return without withdrawals. A prolonged bear market early in your coasting phase can meaningfully extend your full FIRE timeline — the same sequence-of-returns risk that affects early retirees. Building a 10–15% buffer above your calculated Coast FIRE number is the standard guidance to account for this volatility.
Yes — both traditional and Roth IRA balances count toward your invested portfolio. The distinction matters for taxes in retirement (Roth withdrawals are tax-free; traditional IRA and 401(k) withdrawals are taxable income), but for Coast FIRE purposes, the total invested balance is what's relevant. For tax planning, the Roth Conversion Calculator helps model the optimal tax path.
A major market decline can temporarily push your portfolio below the Coast FIRE line. The standard approach is to build a 10–15% buffer — meaning you target a Coast FIRE number 10–15% above the calculated figure — and not to declare victory until you've held the number through at least one down quarter. You may also choose to continue small contributions as insurance. The coast is still far shorter than full FIRE even with that buffer.
7% is the long-run inflation-adjusted compound annual return of U.S. large-cap stocks (S&P 500) from 1926 through 2025, per Ibbotson/Morningstar historical data. It is a historical average, not a guarantee: future returns may be lower, and real-world returns arrive unevenly. For a balanced portfolio including bonds, 5–6% is more appropriate. Running the calculator at both 5% and 7% gives you a realistic planning range.
No — not unless you plan to sell and downsize at retirement. Home equity doesn't generate cash flow for living expenses unless liquidated, and your primary residence is illiquid in ways that investment accounts aren't. Most FIRE practitioners exclude home equity for a conservative margin. If you plan to sell and use the proceeds, you can model that as a one-time addition to your portfolio at your retirement age.
In Coast FIRE, your portfolio grows on its own to cover full retirement — you still work until retirement, but you don't need to save anymore. In Barista FIRE, you semi-retire now on a smaller portfolio, supplemented by part-time income that covers the gap. A Coaster's current job covers all living expenses while the portfolio grows untouched; a Barista's smaller portfolio is already being drawn down, with part-time income filling the gap. Both are valid paths — many people do Coast FIRE first, then shift to Barista FIRE as their portfolio grows. The Barista FIRE Calculator models that hybrid path.
How part-time income shrinks your FIRE number and how many years earlier you can semi-retire.
Plan early retirement.
Calculate your freedom number.
How much can you spend?
Total assets minus total liabilities.
Project portfolio growth.