Coast FIRE at 55 on a $100K Salary
FIRE Number
$1.6M
Target Retirement Age
65
Years to FIRE
10
Monthly Savings Needed
$3K
Coast FIRE at 55 on a $100K salary is is well within reach by maximizing tax-advantaged accounts and investing the surplus. Your FIRE target is $1.6M ($65K/year at 65% income replacement). To coast there from age 55, you need $826K invested by then — that's your Coast FIRE number. At 7% real returns over 10 years, $826K compounds to approximately $1.6M by age 65.
Starting at age 42 with $25K, saving $3K/month for 13 years reaches $826K — a 36% savings rate on your $100K gross income. This is an aggressive savings rate that requires significant lifestyle discipline but delivers the maximum compounding benefit. After 55, you no longer need to save for retirement — you only need to earn enough to cover your $5K/month in living expenses.
The 55-year coast window for $100K earners works particularly well because at 55, you're within striking distance of full retirement account access (at 59½), Rule of 55 benefits, and ultimately Medicare at 65 — making the coast window structurally simple. Social Security at 67–70 adds $3K/month as a meaningful backstop.
One planning note: the $100K + age 55 scenario works best with tax-advantaged account prioritization. Max your employer 401k match ($700/month in free matching at 4%), then Roth IRA ($583/month = $7,000/year), then additional 401k contributions up to $3K/month total. Keeping investment costs low (under 0.1% expense ratio) on a $826K portfolio saves approximately $7K per year in avoided fees — compounding into significant additional wealth over 10 years.