There's a retirement strategy that gives you the freedom of FIRE without the burnout of aggressive saving. It's called Coast FIRE, and it might be the smartest path to early retirement for most middle-class workers. Here's the math, the strategy, and how to know when you've hit it.
Coast FIRE (also written as "Coast FI") is the point in your financial journey when you've saved enough that compound growth alone will get you to your full FIRE number by traditional retirement age (65), even if you stop saving entirely.
The name comes from the idea that you can now "coast" through the rest of your career. You can stop contributing to retirement accounts. You can take a lower-paying but more meaningful job. You can work fewer hours. The savings you have will grow on their own.
This is different from full FIRE (where you can stop working entirely) and different from Lean FIRE (where you can retire on a smaller nest egg). Coast FIRE is a milestone on the way to those goals — but it's a meaningful one because it gives you options.
The formula: Coast FIRE number = Full FIRE number ÷ (1 + real return)^(years until 65)
Where:
Example: You're 30 years old, spending $40,000/year. Your full FIRE number is $1,000,000. You have 35 years until 65. At 7% real return, you need to have saved:
$1,000,000 ÷ (1.07)^35 = $1,000,000 ÷ 10.68 = $93,650
Yes, that's right — only $93,650 invested at age 30, then never saving another dollar, will grow to $1M by age 65 (assuming 7% real return). That's the magic of compound growth over long time horizons.
Assuming $40K annual expenses, $1M full FIRE number, 7% real return:
| Age | Years to 65 | Coast FIRE Number | Multiple of expenses |
|---|---|---|---|
| 25 | 40 | $66,500 | 1.7x |
| 30 | 35 | $93,650 | 2.3x |
| 35 | 30 | $131,950 | 3.3x |
| 40 | 25 | $184,250 | 4.6x |
| 45 | 20 | $258,950 | 6.5x |
| 50 | 15 | $362,450 | 9.1x |
| 55 | 10 | $508,350 | 12.7x |
| 60 | 5 | $712,950 | 17.8x |
The earlier you hit Coast FIRE, the less you need saved. A 25-year-old who saves $66,500 can never save another dollar and still be a millionaire by 65. A 55-year-old needs $508K to coast.
Three reasons Coast FIRE is the most underrated financial milestone:
Once you hit Coast FIRE, the financial pressure is off. Bad day at work? You can quit without panic. Boss asks you to work weekends? You can say no, knowing you can take a year off if needed. This psychological freedom is the #1 underrated benefit.
Most people who try to save 50-70% of income for 10+ years burn out. Coast FIRE is more sustainable because you can drop to 10-20% savings rate after hitting it. The compound growth does the heavy lifting.
Many high-income professionals hate their jobs but feel trapped. Coast FIRE gives them permission to take a 50% pay cut to do work they actually enjoy, because the savings are growing on their own.
Comparison of the main FIRE flavors:
| Type | Savings needed | Work required after | Time to reach (typical) |
|---|---|---|---|
| Coast FIRE | 2-9x expenses | Work for income, but no saving | Age 30-40 |
| Lean FIRE | 20-25x minimal expenses | None — fully retired | Age 40-50 |
| Regular FIRE | 25x current expenses | None — fully retired | Age 45-55 |
| Fat FIRE | 50-100x expenses | None — fully retired | Age 50-60+ |
| Barista FIRE | 15-20x expenses | Part-time, lower-stress | Age 40-50 |
You're saving aggressively but can see the finish line. This is when you start to visualize what post-Coast life looks like. Pick a Coast FIRE number and track your progress toward it.
You've hit the milestone. You can stop saving now and still reach your FIRE number by 65. Most people continue saving at a lower rate because the momentum is there, but you don't have to.
You're so far past the Coast number that you've effectively guaranteed a comfortable retirement. Many people in this stage save less aggressively to enjoy life more now, knowing the buffer is significant.
The discipline is there, the income is there, and you're on a roll. Keep saving 50%+ and reach full FIRE in 5-10 years. This works for people who love the saving optimization game and don't mind working hard for a few more years.
Live on your full salary. Use the extra cash flow for things that bring you joy now — travel, hobbies, nicer home, better food. The savings will compound in the background. You'll reach FIRE later but enjoy life more in the meantime.
The most popular choice. Take a 20-40% pay cut to do work you actually enjoy. The savings continue growing. You might not reach full FIRE as fast, but you'll be happier for the 10-15 years before you do.
Once you hit Coast FIRE, you can take 6-12 months off without touching your investments. The compound growth continues, and you have a runway to figure out what you really want to do next.
Sarah is a software engineer making $130K/year, spending $60K/year. She has been saving aggressively since age 25 and has $200K invested. Her Coast FIRE number at age 32 is $145K — she's already past it.
What she does: Stops maxing out her 401(k), starts a side project, and considers taking a 4-day work week. Her savings still grow at 7%/year and will reach $1.5M by 65. She could potentially retire at 50 with continued saving.
Mike is a public school teacher making $55K/year, spending $40K/year. He's saved $130K in his 403(b) and Roth IRA. His Coast FIRE number at age 38 is $215K — he's at 60% of his target.
What he does: Continues saving $1,000/month. In 7 years, he'll hit Coast FIRE. At that point, he can stop contributing and let it grow. He'll have a comfortable $1M+ by 65 with a teacher's pension on top.
Jenna is a freelance designer making $80K/year with variable income. She spent her 20s aggressively saving and has $90K invested at 28. Her Coast FIRE number is $75K — she's past it.
What she does: Drops her savings rate from 50% to 15%, takes more risks on client projects, takes a 2-month sabbatical. Her savings still grow. She has options now that she didn't have 3 years ago.
The math is the easy part. The hard part is the mindset shift. Hitting Coast FIRE feels different from hitting a savings goal or paying off debt. It's the first time you realize that compound growth can do most of the work for you.
Many people report that after hitting Coast FIRE:
If you hit Coast FIRE at 25 with $66K, that gives you a lot of buffer for 40 years of compound growth. But if you spend aggressively and never save another dollar, you might end up with the right dollar amount but a worse lifestyle than you wanted. Coast FIRE is the "save nothing" baseline, not the "spend everything" target.
The 7% real return is an average. Some 30-year periods have returns of 5%, others 9%. The sequence of returns matters. A bad 10 years at the start of retirement can derail even Coast FIRE plans. Use a more conservative 5-6% for planning, especially if you're closer to retirement.
$1M in 2060 will buy less than $1M today. Your $40K annual expenses in 2026 will be $80K in 2060 if inflation averages 2.5%/year. Factor this in when calculating your Coast FIRE number. A common adjustment: use 1.5-2x your current expenses to be safe.
The biggest Coast FIRE killer is letting your spending explode once you have "permission" to spend. If your lifestyle inflates from $40K to $80K, your Coast FIRE number doubles too. The milestone doesn't give you permission to spend more — it gives you options.
Three steps:
Online calculators make this easy. The key inputs are:
Coast FIRE is especially powerful for high-income professionals (doctors, lawyers, tech, finance) because:
A doctor making $300K/year but hating their job can hit Coast FIRE in 5-7 years, then transition to part-time, concierge medicine, or non-clinical work. The savings they have will grow to $3M+ by 65, providing a comfortable retirement even without peak earning years.
Coast FIRE is also achievable for middle-class earners, just takes longer:
For a $60K earner saving 15% of income ($9,000/year), hitting Coast FIRE at $300K (assuming 7% real return, 30 years to 65) takes about 18 years. The math is unforgiving but not impossible. The key is consistency and avoiding lifestyle inflation.
A common strategy: hit Coast FIRE, then continue working but at a lower-stress, lower-paying job. The savings continue growing in the background. The reduced income makes it easier to save. You might hit full FIRE within 5-10 years of hitting Coast FIRE.
Example timeline:
This is a 20-year plan that doesn't require extreme savings rates. It's sustainable for most people and gives them meaningful career changes along the way.
Coast FIRE is when you've saved enough that compound growth alone will get you to your full FIRE number by traditional retirement age (65), even if you stop saving. You can 'coast' through your career working for the salary alone. Most people hit Coast FI 10-15 years before full FIRE.
Lean FIRE means you can stop working entirely with a smaller nest egg. Coast FIRE means you've saved enough that you could stop saving but still need to work to fully fund retirement. Coast FIRE is a milestone on the way to regular or lean FIRE. It's a 'pause button' for the savings rate, not an exit from work.
Roughly 1/3 to 1/2 of your full FIRE number, depending on how many years until age 65. If your FIRE number is $1M and you're 30, you need about $200K for Coast FIRE. If you're 45, you need about $500K because you have less time for compound growth.
Both work. Coast FIRE is the middle path: less burnout, more flexibility, slower accumulation. Aggressive saving gets you to full FIRE faster but is harder to sustain. Most people benefit from a hybrid: save aggressively early, hit Coast FI, then rebalance to less stressful work.
Three options: (1) Keep saving at the same rate and reach full FIRE years earlier. (2) Stop saving and live on your full salary. (3) Take a lower-paying but more meaningful job. Most people benefit from option 3 — switching to work they actually enjoy once the financial pressure is off.
Use our free calculators to model your FIRE journey:
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