What is Coast FIRE?
You've reached Coast FIRE when your retirement investments are large enough that, with no further contributions, they will grow into your full FIRE number by your planned retirement age. From that point you only need to earn enough to cover current expenses, so you can take a lower-stress job, work part time or take a break, while your nest egg "coasts" to the finish line.
Coast FIRE formula
Coast FIRE number = FIRE number ÷ (1 + real return)^(years to retirement)
Example: you're 30, want to retire at 65 on $50,000 a year, and expect a 6% real return. Your FIRE number at 4% is $1,250,000. Discounted over 35 years, your Coast FIRE number is $1,250,000 ÷ 1.0635 ≈ $162,000. If you already have that invested, you could stop contributing and still be on track.
The calculator also projects when you'll cross your Coast number if you keep saving each month. Because the Coast target rises as retirement gets closer, the crossover happens sooner than you might expect.
Is Coast FIRE risky?
Coast FIRE depends heavily on the return assumption over decades. A 1-point lower real return can nearly double the amount you need today at age 25. Ways to add margin:
- Use a conservative real return (4% to 5%).
- Keep contributing a little, or at least capture any employer 401(k) match.
- Re-run the numbers every year and resume saving if you fall behind.
Frequently asked questions
How is Coast FIRE different from FIRE?
What return should I use for Coast FIRE?
Does Coast FIRE include Social Security?
Last reviewed: 2026-10-09