Investing tools
Practitioner-grade investing calculators. Each tool documents its formula, lists its assumptions, and surfaces the year-by-year math for reproducibility. None of them is investment advice.
- Compound Interest Visualizer
Project the future value of an initial principal plus recurring contributions across any horizon, with a stacked-area chart of principal / contributions / interest.
- FIRE Calculator
Compute your FI number and years to FIRE. Compare Lean, Regular, Fat, Coast, and Barista FIRE side by side.
- US Mortgage Calculator
Monthly P&I and full PITI, complete amortization schedule, automatic PMI handling, extra-payment savings.
- 401(k) vs Roth IRA Optimizer
Compare after-tax retirement value of pre-tax 401(k) vs Roth IRA, accounting for current and retirement marginal rates and employer match.
- Dividend Reinvestment (DRIP)
Project share count, dividend income, and yield-on-cost growth under a DRIP over multi-decade horizons.