InvestingFIRE 🔥 — The #1 Interactive FIRE Calculator
InvestingFIRE is a responsive web application for calculating your path to Financial Independence and Early Retirement (FIRE). It features a year-by-year projection engine that simulates both accumulation (savings and investment growth) and retirement (withdrawals) phases.
Deployed version: https://investingfire.com
🎯 Goal & Vision
Goal
To build the most comprehensive, user-friendly, and transparent open-source financial independence calculator on the web.
Vision
Democratize financial planning by providing professional-grade simulation tools in an accessible, privacy-focused, and beautiful interface. We believe everyone should have the ability to model their financial future without needing a finance degree or expensive software.
Business Model
InvestingFIRE operates on a transparent open-source model:
- Free Forever Core: The essential calculation tools will always be free and open-source.
- Community Supported: We rely on community contributions (code & feedback) to improve the tool.
- Educational Affiliates: We may curate high-quality resources (books, courses, tools) to help users on their journey, keeping the tool free of intrusive ads.
🗺️ Roadmap
We are actively expanding the capabilities of InvestingFIRE. Below is our plan broken down into phases.
Phase 1: Enhanced Simulation (The Engine)
Focus on making the math more robust and flexible.
- Coast FIRE Mode: Option to stop contributions at a certain age but retire later.
- Barista FIRE Mode: Include part-time income during "retirement" years.
- Monte Carlo Simulations: Add probabilistic outcomes (e.g., "95% chance of success") instead of just deterministic linear growth.
- Variable Withdrawal Strategies: Implement dynamic withdrawal rules (e.g., Guyton-Klinger) beyond just fixed inflation-adjusted withdrawals.
Phase 2: User Experience & Persistence
Make the tool easier to use and return to.
- URL State Sharing: Encode form values into the URL so scenarios can be bookmarked and shared.
- Local Persistence: Automatically save user inputs to
localStorageso they don't vanish on refresh. - Currency & Locale Support: Allow users to select currency symbols and number formatting (USD, EUR, GBP, etc.).
Phase 3: Advanced Features & Analytics
For the power users who need more detail.
- Tax Considerations: Simple toggles for Pre-tax vs. Post-tax estimations.
- Scenario Comparison: Compare two different plans side-by-side (e.g., "Retire at 45 vs 55").
- Data Export: Download projection data as CSV or PDF reports.
Phase 4: Content & Community
- Blog/Guides: Integrate a CMS (like Markdown/MDX) for in-depth financial guides.
- Community Presets: "One-click" setups for common strategies (e.g., "Lean FIRE", "Fat FIRE").
🚀 Features at a Glance
- ⚡️ Real-Time Projections: Every field updates the chart as you type. Experiment with savings, growth rates, inflation, or retirement age and see your future instantly.
- 📈 Interactive Chart: Dual-area plots for portfolio value and future monthly spending, plus reference lines for FIRE milestones and “4% rule” legends.
- 🧠 Education Baked In: Contextual tooltips, deep-dive sections on how FIRE works, FAQs, and must-read resources included.
- 🔎 Detailed Methodology: Not just a 25x rule — runs a full, year-by-year simulation with inflation-adjusted withdrawals and optional 4%-rule overlays.
- 👌 Modern UX: Typing, sliding, or clicking feels good. Responsive on all devices.
🧰 How It Works
The calculator models your FIRE journey in two phases:
-
Accumulation:
- Your starting capital is grown by your expected CAGR (~7% by default).
- Monthly savings are added for each year until retirement.
- Every variable can be adjusted live (capital, savings, age, growth, inflation, spending, target retirement).
-
Retirement:
- Your balance continues to grow by CAGR.
- Each year, an inflation-adjusted monthly allowance is withdrawn.
- The simulation runs until your selected life expectancy, showing the possibility of portfolio depletion.
Key Outputs:
- 🔥 “FIRE Number”: Portfolio value at your defined retirement age
- 📊 Interactive projection chart: See how your nest egg and withdrawals evolve over time
- 4️⃣ “4% Rule” overlays: Compare dynamic results to classic rule-of-thumb
🌟 Try It For Yourself
To run locally:
- Clone the repo
git clone https://git.schulze.network/schulze/fire.git cd fire - Install dependencies
pnpm install - Run the app
pnpm run dev - Visit http://localhost:3000 and unleash the fire.
✏️ Inputs & Variables
- Starting Capital — How much you’ve already invested
- Monthly Savings — What you’ll add each month
- Current Age & Retirement Age — Your FI timeline
- Life Expectancy — How long do you want income to last?
- Expected Growth Rate (CAGR) — Portfolio annual % return, before inflation
- Inflation Rate — Cost of living increases
- Desired Monthly Allowance — Your lifestyle, today’s dollars
As you adjust these, all projections update instantly without needing to hit “Calculate.”
Try many “what ifs” fast.
👩💻 Contributing
Pull requests are welcome! Open issues for bugs, new features, or debate about safe withdrawal rates and tax assumptions.
📄 License
🥇 Why Use InvestingFIRE?
- You want the truth — not just a 4% fantasy.
- You want to learn, not just punch in numbers.
- You want clarity, speed, and modern UI.
- You want to show your friends the best FIRE tool on the web.
Enjoy the rocket ride to financial independence.
InvestingFIRE — Know your number. Change your future.