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, allowing users to:
- Input starting capital, monthly savings, expected annual growth rate, inflation rate, current age, desired retirement age, life expectancy, and desired monthly retirement allowance.
- View a dynamic chart displaying projected portfolio balance and monthly allowance over time.
- Instantly see their estimated “FIRE number” (required capital at retirement), how long their capital will last, and compare results to the “4% rule.”
- Adjust assumptions live, with all calculations and visualizations updating automatically.
- Access explanatory content about FIRE methodology, key variables, and additional community resources, all on a single, consolidated page.
The project’s code is structured using React/Next.js with TypeScript, focusing on user experience, modern UI components, and clarity of financial assumptions.
🚀 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- Each year, an inflation-adjusted monthly allowance is withdrawn.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
npm install - Run the app
npm run dev - Visit http://localhost:3000 and unleash the fire.
Deployed version: https://investingfire.com
✏️ 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.