FIRE Planner
Put retirement spending, passive income, cash reserve, and compounding into one decision surface to see whether your target makes sense.
1. Current Position
This defines how far you are from the target today.
Use the net financial assets that can realistically support FIRE.
After-tax, durable income is more useful than peak months.
Use real lifestyle costs and avoid underestimating fixed spend.
Monthly Net Savings
¥8,000
Savings Rate
40%
2. Growth Assumptions
These control compounding speed and withdrawal safety.
Use an after-tax, after-inflation expectation, not a recent bull market number.
3.5% to 4.5% is a common range. Lower means more conservative.
3. Retirement Assumptions
These define what the FIRE target is made of.
Estimate the lifestyle cost you expect after leaving full-time work.
Examples: rent, pension, annuity, part-time work, or other stable cash flow.
Keeping 6 to 24 months of expenses in lower-volatility assets is a practical default.
Retirement Gap
¥10,000/mo
Results auto-refresh after changes. Use the button if you want to refresh immediately.
Run the first projection
After you fill in the inputs, this panel will show time to goal, target composition, and the growth path.
Target Assets = Annual Retirement Gap / Withdrawal Rate + Post-FIRE Monthly Expense × Cash Buffer Months
This replaces the less intuitive investment-ratio model with a buffer measured directly in months.
End-of-Month Assets = Start-of-Month Assets × (1 + Monthly Return) + Monthly Net Savings
Savings are added at month end, which is slightly more conservative than assuming month-start contributions.
Annual Retirement Gap = max(Post-FIRE Monthly Expense - Other Monthly Income, 0) × 12
First measure how much spending still needs to be funded by the portfolio, then size the corpus.
Monthly Return = (1 + Annual Return)^(1/12) - 1
This uses an effective monthly rate instead of the simpler Annual / 12 shortcut.
This tool is designed for strategy and decision support, not as professional financial advice.