Coast FIRE Explained: Stop Saving and Still Retire Early

What If You Could Stop Saving?

Coast FIRE is the financial milestone where you've saved enough that compound growth alone will carry your portfolio to your full Quit Number by your target retirement age — without another dollar of contributions.

Once you reach Coast FIRE, you only need to earn enough to cover your current expenses. No more saving. No more investing. Just live your life and let the math do its thing.

How the Math Works

The formula is simple. If your Quit Number is $1,500,000 and you plan to quit at age 55, compound growth at 7% per year means:

• At age 25 (30 years of growth): You need $197,000 today to coast. ($197,000 × 1.07^30 = $1,500,000)
• At age 30 (25 years of growth): You need $276,000 today to coast.
• At age 35 (20 years of growth): You need $388,000 today to coast.
• At age 40 (15 years of growth): You need $544,000 today to coast.
• At age 45 (10 years of growth): You need $763,000 today to coast.

The earlier you start, the less you need. At 25, less than $200,000 invested means you're done saving for retirement. Everything you earn from that point forward is for living today.

What Changes When You Hit Coast FIRE

Reaching Coast FIRE unlocks options that weren't available before:

Switch Careers

Take that lower-paying job you've always wanted. Teach, write, do nonprofit work, or start a business. You don't need the income for retirement savings anymore — just enough to cover today's bills.

Work Part-Time

Drop to 3 or 4 days a week. Negotiate remote work. Take unpaid leave. You can afford the flexibility because your future is already funded.

Take Risks

Start a business without the terrifying "what if it fails?" question. Your retirement savings keep growing regardless of what happens with the venture.

Relocate

Move to a lower cost-of-living area. Your Coast FIRE number doesn't change, but your day-to-day expenses drop, making it even easier to cover costs with a relaxed income.

Coast FIRE vs. Regular FIRE

With regular FIRE, you keep saving aggressively until you hit your full Quit Number, then stop working entirely. With Coast FIRE, you stop saving when compound growth can finish the job, but you keep earning enough to cover expenses.

The trade-off is clear: Coast FIRE arrives sooner, but you still work (just without the pressure). Regular FIRE takes longer, but you stop working completely.

For many people, the years between Coast FIRE and regular FIRE are the best of their working lives — because the pressure is gone.

When Coast FIRE Doesn't Work

A few scenarios where coasting is risky:

• You're close to your target age. If you only have 5-10 years until your target retirement, compound growth doesn't have much time. Coasting requires a long runway.
• Your Quit Number is very high. If your expenses are high and your Coast Number is large, you might reach regular FIRE before you'd reach Coast FIRE anyway.
• Market returns below 7%. The 7% assumption is historical average for U.S. stocks. Lower returns mean a higher Coast Number. Consider using 5-6% for a more conservative estimate.

A Real Example

Meet Chris, age 32. Chris earns $90,000, spends $4,000/month ($48,000/year), and has $250,000 invested.

Chris's Quit Number: $48,000 × 25 = $1,200,000. Target quit age: 50 (18 years away).

Coast Number: $1,200,000 / 1.07^18 = $354,000.

Chris needs $354,000 to coast. With $250,000 already invested and saving $3,500/month, Chris will hit the Coast Number in about 2.5 years.

After that, Chris could take a job earning $48,000/year — just enough to cover expenses — and stop investing entirely. The $354,000 grows on its own to $1.2M by age 50.

Find Your Coast Number

Start by calculating your Quit Number. Once you know your target and your current savings, you can calculate whether compound growth alone can get you there. The answer might surprise you — many people are closer to Coast FIRE than they realize.