Coast FIRE Calculator
Calculate your Coast FIRE number, the amount you need invested today so that compound growth alone will get you to your retirement number. After this, you can stop saving for retirement and just cover current expenses.
Reviewed & updated for 2026 · How we calculate
Coast FIRE numbers at common ages
| Current age | $1M FIRE goal | $1.5M FIRE goal | $2M FIRE goal |
|---|---|---|---|
| 25 (retire at 65) | $67,000 | $100,000 | $133,000 |
| 30 (retire at 65) | $94,000 | $141,000 | $188,000 |
| 35 (retire at 65) | $132,000 | $197,000 | $263,000 |
| 40 (retire at 65) | $184,000 | $277,000 | $369,000 |
| 45 (retire at 65) | $258,000 | $388,000 | $517,000 |
| 50 (retire at 65) | $363,000 | $544,000 | $725,000 |
Assumes 7% real return. Lower returns require larger Coast FIRE numbers.
Why Coast FIRE happens earlier than people expect
Most people imagine retirement savings as a long, linear climb — save X dollars a year for 40 years and you'll get there. Coast FIRE is the realization that the climb is actually front-loaded. Almost all of your retirement balance comes from growth on the money you saved before age 40, not from contributions made afterwards.
Consider a 30-year-old with $150,000 invested. At a 7% real return, that money will grow to $1.14 million by age 65 with zero additional contributions. The 35 years of compounding does the work. The same person would need to start fresh at age 50 and save $4,500 a month for 15 years to reach the same number.
This is why Coast FIRE is mathematically achievable for many middle-class earners by their late 30s or early 40s — you only need to save aggressively for 10 to 15 years, then the market does the rest.
| Save aggressively until age | Balance at that age | Coast value at 65 |
|---|---|---|
| 35 (10 years of saving) | $200,000 | $1,522,000 |
| 40 (15 years of saving) | $350,000 | $1,902,000 |
| 45 (20 years of saving) | $550,000 | $2,128,000 |
| 50 (25 years of saving) | $800,000 | $2,205,000 |
Assumes saving $1,500/month from age 25 to the stop age, 7% real return.
What "coasting" looks like in real life
Coast FIRE doesn't mean quitting work. It means your retirement savings problem is solved, so the rest of your career becomes about covering today's bills, not building a nest egg. People use the freedom in different ways:
- Career pivots. A software engineer takes a 40% pay cut to teach high school computer science. Without Coast FIRE, the lost retirement contributions would matter. With it, today's salary just needs to cover today's expenses.
- Going part-time. Cutting back to 25-30 hours a week so you can pick up kids, write a novel, or train for a marathon. The reduced income still covers expenses; retirement is already on autopilot.
- Founder leaps. Starting a business while collecting modest consulting income on the side. Coast FIRE eliminates the "what if this fails?" retirement worry — your future self is fine either way.
- Geographic arbitrage. Moving to a lower-cost city or abroad. Less income works, since the retirement math is solved.
- Sabbaticals. Taking 6-12 months off mid-career for travel, caregiving, or a degree. Burn through savings without ruining retirement.
The risks: a market crash early in your coasting period can knock you off track, you'll likely still want to save for healthcare and emergencies, and Social Security assumptions could change. Most Coast FIRE practitioners keep contributing at a reduced rate (5% of income instead of 20%) as insurance against bad sequence-of-returns luck.
FAQs
What is Coast FIRE?
Coast FIRE means you've saved enough that your investments will compound to your full retirement number BY the time you retire, even if you stop adding new contributions. You still need to work to pay expenses, but you don't need to save more for retirement. It's a 'partial' FIRE status, financially independent for retirement, not yet for current expenses.
How is Coast FIRE different from regular FIRE?
Full FIRE = enough invested to cover ALL expenses today (typically 25x annual expenses). Coast FIRE = enough invested that compound growth alone will reach full FIRE by retirement age. Coast FIRE requires LESS savings now but still working. Lean FIRE = covering bare-minimum expenses. Fat FIRE = covering luxury lifestyle.
What's the Coast FIRE formula?
Coast FIRE number = FIRE number / (1 + return rate)^(years to retirement). Example: Need $1.5M at age 65. You're 35. Expected real return: 7%. Coast FIRE = 1,500,000 / 1.07^30 = 197,000. If you have $197K invested today, you can stop saving and reach $1.5M by age 65 from growth alone.
What's a realistic Coast FIRE age?
Common patterns: aggressive savers can hit Coast FIRE by mid-30s. Mid-tier savers (15-20% savings rate) typically hit Coast FIRE in late 30s to mid-40s. The earlier you Coast FIRE, the more years of compound growth, and the smaller the Coast FIRE number needed today.
What return rate should I use?
Historical S&P 500 real return (after inflation): 7-7.5%. Conservative: 5-6%. If retiring early or worried about sequence-of-returns risk: use 5%. If young with long time horizon: 7% is reasonable. Lower rate = more required savings now.
Should I keep saving after hitting Coast FIRE?
Up to you. Many Coast FIRE achievers do keep saving, they reduce contributions but don't stop entirely, building safety margin. Others 'coast' aggressively, lowering income to do more fulfilling work. Some downshift to part-time, freelance, or career pivots. Coast FIRE gives you OPTIONS, not a prescription.