What Is Coast FIRE?
Coast FIRE is a milestone within the FIRE movement. It answers one question: how much do you need invested today so that compound growth alone — with zero further contributions — reaches your full retirement number by the time you want to retire?
Once you reach Coast FIRE, you no longer need to save for retirement. You still need to earn enough to cover your current living expenses, but the financial pressure of aggressive retirement saving is gone. You can take a lower-paid job you enjoy, go part-time, or simply have more spending money each month.
The Formula
FIRE Number = Annual Expenses ÷ Safe Withdrawal Rate
Real Return = Growth Rate − Inflation Rate
Coast FIRE Number = FIRE Number ÷ (1 + Real Return)^Years to Retirement
This calculator uses the inflation-adjusted (real) return rate so all values are expressed in today's purchasing power. The green line adds your monthly contributions. The blue line shows what happens if you stop contributing at the Coast FIRE milestone and just let the portfolio compound.
Coast FIRE Numbers at Different Ages
Assuming €40.000 annual spend, 4% SWR (FI number €1.000.000), 7% growth, 2,5% inflation, retiring at 65.
| Current Age | Years to 65 | Real Return | Coast FIRE Number |
|---|
| 25 | 40 | 4,5% | €171.929 |
| 30 | 35 | 4,5% | €213.901 |
| 35 | 30 | 4,5% | €266.010 |
| 40 | 25 | 4,5% | €330.878 |
| 45 | 20 | 4,5% | €411.587 |
| 50 | 15 | 4,5% | €512.069 |
| 55 | 10 | 4,5% | €637.214 |
Frequently Asked Questions
Why does this calculator use real return instead of nominal?+
Using the real return (growth rate minus inflation) means all values in the chart and results are expressed in today's purchasing power. You enter your retirement expenses in today's money — this approach automatically accounts for inflation without requiring you to inflate your future target separately. It is the cleanest way to think about long-term financial planning.
What does the blue line on the chart show?+
The blue line shows your portfolio value if you stop making monthly contributions at the exact moment you hit Coast FIRE, and let the portfolio compound on its own from that point forward. The green line shows your portfolio if you keep contributing every month all the way to retirement. Both lines should reach the FIRE number (red dashed line) by your retirement age.
What is a safe withdrawal rate and should I use 4%?+
The 4% rule comes from the Trinity Study, which showed a 4% annual withdrawal had a very high historical success rate over 30 years with a balanced portfolio. For longer retirements — say 40 or 50 years — some planners use 3% or 3,5% to be more conservative. Adjust the SWR slider to see how it changes your Coast FIRE number.
Can I still contribute after hitting Coast FIRE?+
Absolutely. Coast FIRE means you no longer need to — but continuing to invest simply accelerates your retirement date. Many people who hit Coast FIRE keep investing at a reduced rate and retire earlier than their original target age.
What counts as invested assets in this calculator?+
Include pension pots, brokerage accounts, ISAs, ETF holdings, index funds, and any other invested assets. Do not include your emergency fund, cash, or the equity in your primary home — these are not liquid invested assets that compound at market rates.