Personal Finance Calculators
Interactive client-side financial engines with the math shown. Run computational models for downside loss recovery, exponential compound growth, systematic DCA, inflation decay, CAGR, and early retirement milestones.
Safe Withdrawal Rate Simulator
Test retirement portfolio longevity across 10,000 Monte Carlo simulations and dynamic spending guardrails. See empirical failure rates and sequence-of-returns drag, not static projections.
CAGR Calculator
CAGR = (End / Start)^(1 / years) - 1Calculate the compound annual growth rate, total percentage return, and annual progression across any investment horizon.
- #compounding
- #returns
XIRR Calculator
sum( C_i / (1 + r)^((d_i - d_0) / 365) ) = 0Calculate the annualized internal rate of return for irregular cash flow schedules, periodic deposits, and withdrawals.
- #xirr
- #cash-flow
- #returns
- #compounding
Loss Recovery Calculator
Gain Required = L / (1 - L)Calculate the percentage gain required to recover from a portfolio loss using the formula L / (1 - L).
- #Drawdown Recovery
- #Portfolio Asymmetry
- #Capital Preservation
- #Risk Management
Compound Interest Simulator
A = P(1 + r/n)^{nt} + PMT * [((1 + r/n)^{nt} - 1) / (r/n)]Model exponential capital feedback loops with scheduled monthly contributions and custom compounding intervals.
- #compounding
- #growth
Dollar-Cost Averaging (DCA)
Average Cost = Total Invested / Total Shares PurchasedSimulate automated periodic asset allocation across volatile and down-trending price regimes to reduce downside variance.
- #dca
- #execution
Inflation Calculator
Future Cost = Amount × (1 + i)^n | Real Return = (1 + r) / (1 + i) - 1Calculate future purchasing costs, discount future cash to today's value, and compute exact Fisher real returns across any inflation horizon.
- #inflation
- #purchasing-power
- #real-returns
Rule of 72 calculator
Years to Double ≈ 72 / r | Exact: t = ln(2) / ln(1 + r/100)Estimate how long money takes to double, or the return you need to double in a set time. Compare the shortcut with the exact answer.
- #rule-of-72
- #compounding
- #mental-models
- #doubling-time
RSU-to-Housing Opportunity Cost Calculator
Gap = Path A Net Worth - Path B Net WorthCompare selling vested company equity for a home down payment versus keeping equity invested in markets, renting, and investing monthly cash flow differentials.
- #RSU Equity
- #Real Estate Opportunity Cost
- #Capital Gains Tax Drag
- #Mortgage Amortization
- #Markov State Machine
Tech-Worker Relocation and State Tax Delta Simulator
Net Surplus Delta = (TakeHome_{To} - COL_{To}) - (TakeHome_{From} - COL_{From})Compare net take-home pay, cost of living, and multi-year investable surplus when moving between high-tax states (CA/NY) and no-income-tax states (TX/WA).
- #taxes
- #relocation
- #cost of living
- #investing
- #equity compensation
Startup Equity vs FAANG Cash-Flow Modulator
PV_{Net} = \sum_{t=1}^H \frac{CashFlow_t - Taxes_t}{(1 + r)^t} + \frac{\max(0, \text{OptionGain}_H - \text{ExitTax}_H)}{(1 + r)^H}Compare big-tech cash and liquid RSUs against startup equity under multiple volatility curves, liquidation preferences, dilution, and CRRA risk preferences.
- #equity compensation
- #startups
- #rsu
- #stock options
- #risk analysis
- #taxes
FIRE and Coast FIRE calculator
FIRE Number = Retirement Expenses / SWRFind the portfolio you need to retire early, and the point where you can stop saving and let compounding finish the job.
- #retirement
- #compounding
- #financial-independence
- #coast-fire
Fee drag calculator
Net Annual Return = Gross Return − Total Fee Rate | Monthly Rate = (1 + Net)^(1/12) − 1 | Balance_m = Balance_(m−1) · (1 + Monthly Rate) + ContributionSee what investment fees cost over time. Compare funds by expense ratio and see the difference in your final balance.
- #fees
- #expense-ratio
- #compounding
- #index-funds
Related Guides & References
Explore first-principles written guides, mathematical proofs, and technical glossaries explaining these models.
Safe Withdrawal Rate Simulator
Run 10,000 Monte Carlo iterations to test retirement portfolio failure rates and dynamic spending guardrails.
Financial Systems Glossary
Technical definitions and mathematical models for Volatility, Diversification, Ruin Barriers, and Drawdowns.
Compound Interest Feedback Loops
Deep-dive educational pillar guide on exponential capital curves, mathematical recurrence, and friction.
Dollar-Cost Averaging Guide
Mathematical foundation and volume-weighted accumulation mechanics during volatile market regimes.
Technical Market Indicators
Mathematical reference implementations of RSI, MACD, Bollinger Bands, and Moving Averages.