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Coast FIRE means you have saved enough that compound growth alone will reach your full FIRE number by age 60, even if you never invest another dollar. At age 30, that number is roughly $164,000 (for $50K/year expenses). At 35, it is about $230,000. Once you cross that line, you can stop saving aggressively and just earn enough to cover current expenses.
This is not full retirement. You still work. But you work without the pressure of maximizing savings, funding 401ks, or feeling guilty about spending your paycheck. The retirement problem is solved. You just need income for today.
The formula:
Coast FIRE Number = Full FIRE Number ÷ (1 + return rate)^years to target age
Step by step:
If you have $157,897 invested at age 32, earning 7% real returns, it grows to $1,050,000 by age 60. You can coast.
Quick way to check with our calculator: Open the FIRE calculator, set monthly income = monthly expenses (so savings = $0), and enter your current savings. If it shows you reaching your FIRE number within the years you have left until 60, you have Coast FIRE.
Check if you have reached Coast FIRE — set income = expenses in the calculator.
Open FIRE Calculator →For a $1,250,000 FIRE number ($50K/year expenses at 4% SWR), targeting age 60:
| Your Age | Years to 60 | Coast FIRE @ 7% | Coast FIRE @ 6% | Coast FIRE @ 5% |
|---|---|---|---|---|
| 22 | 38 years | $96,000 | $127,000 | $171,000 |
| 25 | 35 years | $117,000 | $150,000 | $195,000 |
| 28 | 32 years | $144,000 | $178,000 | $224,000 |
| 30 | 30 years | $164,000 | $199,000 | $243,000 |
| 32 | 28 years | $188,000 | $222,000 | $264,000 |
| 35 | 25 years | $231,000 | $262,000 | $300,000 |
| 37 | 23 years | $264,000 | $293,000 | $327,000 |
| 40 | 20 years | $323,000 | $345,000 | $374,000 |
| 42 | 18 years | $370,000 | $387,000 | $408,000 |
| 45 | 15 years | $453,000 | $458,000 | $463,000 |
| 48 | 12 years | $554,000 | $543,000 | $527,000 |
| 50 | 10 years | $635,000 | $611,000 | $578,000 |
Notice how the 5% column approaches and eventually exceeds the 7% column at older ages. That is because less compounding time means return rate matters less and starting balance matters more.
The 7% column is the optimistic scenario (historical S&P 500 average after inflation). The 5% column is the conservative scenario. Most Coast FIRE practitioners target somewhere between these — enough to be confident but not so conservative that the number becomes unachievably high.
| Annual Expenses | FIRE Number (4% SWR) | Coast FIRE at 30 | Coast FIRE at 35 | Coast FIRE at 40 |
|---|---|---|---|---|
| $25,000 (Lean) | $625,000 | $82,000 | $115,000 | $161,000 |
| $35,000 | $875,000 | $115,000 | $161,000 | $226,000 |
| $42,000 | $1,050,000 | $138,000 | $194,000 | $271,000 |
| $50,000 | $1,250,000 | $164,000 | $231,000 | $323,000 |
| $60,000 | $1,500,000 | $197,000 | $277,000 | $387,000 |
| $80,000 | $2,000,000 | $263,000 | $369,000 | $517,000 |
| $100,000 (Fat) | $2,500,000 | $328,000 | $461,000 | $646,000 |
All at 7% real return, 4% SWR, targeting age 60.
You have hit your Coast FIRE number. Now what changes?
| Type | What It Means | Portfolio Needed | Still Working? |
|---|---|---|---|
| Coast FIRE | Compound growth handles retirement savings | $100K-400K (age dependent) | Yes — but only to cover current expenses |
| Barista FIRE | Part-time work covers expenses + health insurance | $500K-800K | Yes — part-time, low stress |
| Lean FIRE | Fully retired on minimal expenses | $500K-1M | No — fully retired |
| Regular FIRE | Fully retired on moderate expenses | $1M-1.5M | No — fully retired |
| Fat FIRE | Fully retired on comfortable expenses | $2.5M+ | No — fully retired |
Coast FIRE is not retirement. It is freedom from the obligation to save. That distinction matters because it is achievable much faster than full FIRE — often in your early 30s with aggressive saving from 22 to 30.
The math works at 7%. But what if the next 30 years average 5% real returns instead?
At 5%, your $164,000 at age 30 grows to only $709,000 by age 60 — well short of $1,250,000. You would need to have saved $289,000 at age 30 to coast safely at 5% returns.
This is why many Coast FIRE practitioners:
Use our compound interest calculator to model what your portfolio looks like at different return rates over 25-35 years. Run it at 5%, 6%, and 7% to see the range of outcomes. If your plan survives the 5% scenario, you are in strong shape.
Check your Coast FIRE number — are you closer than you think?
Open FIRE Calculator →