Retirement Fund Calculator / FIRE Calculator | Spending and Required Fund Simulation
Compare projected retirement assets with the required retirement fund using assets, savings, retirement age, life expectancy, and spending assumptions. The existing FIRE view remains available.
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Design your journey toward FIRE (Early Retirement)
FinMap FIRE Simulator analyzes your FIRE timing and post-retirement sustainability using real after-tax returns.
FINMAP · FIRE MODEL · REAL RETURN BASED
Example FIRE curve (real return)
FIRE Rule
Spend ÷ WR
Key Inputs
Return · WR · Infl
Model Based
Real Return
How to use this FIRE calculator
FinMap FIRE calculator estimates FIRE timing and post-retirement asset sustainability using real after-tax returns.
- FIRE Target = Annual spending ÷ Withdrawal rate (e.g., 4% rule)
- Real Return reflects actual investment growth after tax, fee, and inflation adjustments.
- Simulates the accumulation and retirement phases separately.
- Provides visual curves to highlight FIRE timing and depletion risk.
- Adjust return, inflation, and withdrawal assumptions to check how sensitive the result is.
Assumption base date: 2026-04-30
This simulation uses your inputs for assets, savings, returns, tax, fees, inflation, and withdrawal rate in a simplified model. Results are estimates for planning, not investment advice or a guarantee of retirement readiness.
Not modeled: pension cash flows, tax-law changes, healthcare costs, medical/family support expenses, and post-retirement spending growth.
Verified calculation core
Detailed retirement inputs
Enter age, retirement age, life expectancy, monthly expense, savings, and returns to compare projected assets with the retirement fund needed.
Money inputs are in Korean won (KRW).
A-D are the same verified samples used by the test script.
Key summary
Projected retirement assets
₩943,638,754
Required retirement fund
₩1,308,767,883
Surplus / shortfall
-₩365,129,129
Achievement rate
72.10%
Retirement-date expense
Sustainable spending
Required monthly saving
₩1,613,137
₩1,000,000
₩613,137
This is a simulation based on the inputs. Additional monthly saving: ₩613,137
Interpretation: Adjust saving, retirement age, or spending
This is a simulation based on the inputs. Changing return, inflation, retirement timing, or spending can materially change the result.
Sensitivity analysis
| Scenario | Projected retirement assets | Required retirement fund | Surplus / shortfall | Achievement rate |
|---|---|---|---|---|
| Pre-retirement return -1pp | ₩785,506,063 | ₩1,308,767,883 | -₩523,261,820 | 60.02% |
| Base pre-retirement return | ₩943,638,754 | ₩1,308,767,883 | -₩365,129,129 | 72.10% |
| Pre-retirement return +1pp | ₩1,139,490,944 | ₩1,308,767,883 | -₩169,276,939 | 87.07% |
| Base retirement age | ₩943,638,754 | ₩1,308,767,883 | -₩365,129,129 | 72.10% |
| Retirement age +3 years | ₩1,134,763,544 | ₩1,249,203,927 | -₩114,440,382 | 90.84% |
| Retirement age +5 years | ₩1,279,033,067 | ₩1,198,865,098 | ₩80,167,969 | 106.69% |
| Monthly expense -10% | ₩943,638,754 | ₩1,177,891,095 | -₩234,252,341 | 80.11% |
| Base monthly expense | ₩943,638,754 | ₩1,308,767,883 | -₩365,129,129 | 72.10% |
| Monthly expense +10% | ₩943,638,754 | ₩1,439,644,671 | -₩496,005,918 | 65.55% |
Year-by-year asset path
| Age | Elapsed years | Projected assets | Cumulative saving | Estimated investment gain | Target progress |
|---|---|---|---|---|---|
| 40 | 0y | ₩100,000,000 | ₩0 | ₩0 | 7.64% |
| 41 | 1y | ₩117,395,045 | ₩12,000,000 | ₩5,395,045 | 8.97% |
| 42 | 2y | ₩135,680,054 | ₩24,000,000 | ₩11,680,054 | 10.37% |
| 43 | 3y | ₩154,900,559 | ₩36,000,000 | ₩18,900,559 | 11.84% |
| 44 | 4y | ₩175,104,421 | ₩48,000,000 | ₩27,104,421 | 13.38% |
| 45 | 5y | ₩196,341,951 | ₩60,000,000 | ₩36,341,951 | 15.00% |
| 46 | 6y | ₩218,666,033 | ₩72,000,000 | ₩46,666,033 | 16.71% |
| 47 | 7y | ₩242,132,258 | ₩84,000,000 | ₩58,132,258 | 18.50% |
| 48 | 8y | ₩266,799,059 | ₩96,000,000 | ₩70,799,059 | 20.39% |
| 49 | 9y | ₩292,727,861 | ₩108,000,000 | ₩84,727,861 | 22.37% |
| 50 | 10y | ₩319,983,229 | ₩120,000,000 | ₩99,983,229 | 24.45% |
Simple FIRE calculator
Simple FIRE calculator: estimate target assets and asset longevity using annual spending and withdrawal rate.
Recommended guides
View all postsFIRE Calculator FAQ
How is the FIRE target calculated?
FIRE target = Annual spending ÷ Withdrawal rate (e.g., 4% rule).
What is nominal return?
Return before adjusting for tax, fees, and inflation.
How does the withdrawal rate affect FIRE?
Higher withdrawal rates require larger FIRE target assets and increase depletion risk.
How is tax applied?
Tax is applied to investment returns. This calculator uses nominalAfterTax = (nominal return - fee) × (1 - tax), then real return = (1 + nominalAfterTax) ÷ (1 + inflation) - 1.
What does the fee represent?
ETF/fund fees and brokerage costs that reduce long-term growth.
Why is inflation important?
Inflation reduces purchasing power and must be included in FIRE assumptions.
How is real return calculated?
Real return = (1 + (nominal return - fee) × (1 - tax)) ÷ (1 + inflation) - 1. It reflects purchasing-power growth after estimated tax, fees, and inflation.
Why show real vs nominal assets?
Nominal = account balance, Real = inflation-adjusted purchasing power.
What does depletion year mean?
The year assets reach zero after withdrawals and growth.
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