Coast FI: How to Stop Saving Early and Still Retire Comfortably

Coast FI is the most underrated milestone on the path to financial independence. It is the moment your invested portfolio is large enough that — even if you never contribute another dollar — it will grow into a full retirement nest egg by traditional retirement age. From that day forward, you only need to cover current expenses.

The Coast FI formula

Coast FI = (Annual expenses × 25) / (1 + r)^n, where r is your assumed real return and n is years to traditional retirement. At a 5% real return and 30 years out, a 30-year-old needs only ~23% of their final FI number invested to hit Coast FI.

Why it changes everything

Once you hit Coast FI, your income only needs to cover current spending — not future investing. You can switch to a lower-stress job, work part-time, take a sabbatical, or change careers without putting retirement at risk.

A concrete example

Maya is 32, spends $50k/year, wants to retire at 62. Her FI number is $1.25M. Coast FI at 5% real returns: $1.25M / (1.05)^30 ≈ $289k. Once Maya has $289k invested, she can coast — and her portfolio still grows to $1.25M by age 62.

How to reach Coast FI fast

1. Front-load aggressively in your 20s and early 30s while expenses are low.
2. Max tax-advantaged accounts first — 401(k), Roth IRA, HSA.
3. Capture every employer match.
4. Avoid lifestyle inflation in your highest-saving years.
5. Stay in low-cost index funds; minimize fees.

Lifestyle decisions Coast FI enables

• Drop to 32 hours/week with a 20% pay cut you can now afford
• Start a business with a longer payoff timeline
• Take a 6–12 month sabbatical without panic
• Geographic arbitrage: move to a lower cost area on lower income
• Career pivot into a lower-paying field you care about

The risks to acknowledge

Coast FI assumes your return assumption holds, your expenses do not balloon, and you do not need to retire before traditional age. It is not a guarantee — it is a high-probability glide path. A market crash early in your coasting years can require resumed contributions for a few years.

Calculate your Coast FI number

The Financial Freedom Calculator shows your full FI timeline. To find Coast FI, take your FI target and discount it back by your expected return rate to your current age. Many people are within a few years of Coast FI without realizing it.