Coast FIRE at 40 on a $300K Salary
FIRE Number
$4.9M
Target Retirement Age
65
Years to FIRE
25
Monthly Savings Needed
$4K
Coast FIRE at 40 on a $300K salary is can be reached very quickly — the primary challenge is avoiding the lifestyle creep that erodes high-income savings rates. Your FIRE target is $4.9M ($196K/year at 65% income replacement). To coast there from age 40, you need $898K invested by then — that's your Coast FIRE number. At 7% real returns over 25 years, $898K compounds to approximately $4.9M by age 65.
Starting at age 30 with $75K, saving $4K/month for 10 years reaches $898K — a 17% savings rate on your $300K gross income. This is a very achievable savings rate — even a standard 401k contribution plus employer match covers a large portion of it. After 40, you no longer need to save for retirement — you only need to earn enough to cover your $16K/month in living expenses.
The 40-year coast window for $300K earners works particularly well because you have 25+ years of compounding ahead — enough time for the portfolio to recover from multiple market cycles while growing to your full FIRE number. Social Security at 67–70 adds $3K/month as a meaningful backstop.
One planning note: the $300K + age 40 scenario works best with tax-advantaged account prioritization. Max your employer 401k match ($2000/month in free matching at 4%), then Roth IRA ($583/month = $7,000/year), then additional 401k contributions up to $4K/month total. Keeping investment costs low (under 0.1% expense ratio) on a $898K portfolio saves approximately $8K per year in avoided fees — compounding into significant additional wealth over 25 years.