Best FIRE Calculator 2026: 8 Free Tools Compared
Published June 2026 · 8 min read
Finding the right FIRE calculator can make or break your early retirement planning. After testing over a dozen tools, we narrowed the list down to the 8 best free FIRE calculators that actually work — each evaluated on accuracy, privacy, ease of use, and unique features. Whether you are new to the FIRE movement or already tracking your progress toward financial independence, this guide will help you pick the right tool.
How We Evaluated Each Calculator
- Accuracy — Does it use the correct 4% rule math and compound growth formulas?
- Privacy — Does your financial data stay on your device, or is it sent to a server?
- Ease of Use — Can you get results in under 30 seconds without reading a manual?
- Features — Does it support Lean/Regular/Fat FIRE modes? Coast FIRE? Charts?
- Free Access — No sign-up, no paywall, no email required.
Comparison Table
| Calculator | FIRE Modes | Charts | Privacy | Free |
|---|---|---|---|---|
| PlanFolio ⭐ | Lean, Regular, Fat | Interactive | Browser-only | ✅ |
| FIRECalc.com | Standard only | Basic | Browser-only | ✅ |
| fire-calc.com | Advanced | Interactive | Browser-only | ✅ |
| calculator.net | Standard only | None | Server | ✅ |
| firenum.com | 8 modes | Interactive | Browser-only | ✅ |
| myfirenumber.com | 9 modes | Recharts | Browser-only | ✅ Open-source |
| coastfirecalc.io | Coast only | Basic | Browser-only | ✅ |
| theficalculator.com | Standard + Barista | None | Server | ✅ |
Detailed Reviews
1. PlanFolio FIRE Calculator ⭐ — Best Overall
PlanFolio's FIRE Calculator is our top pick for 2026. It supports Lean, Regular, and Fat FIRE modes with a single toggle, provides an interactive Chart.js visualization of your portfolio growth over time, and runs entirely in your browser — your financial data never leaves your device. The built-in FAQ section explains key concepts like the 4% rule and FIRE number calculation right on the calculator page. No sign-up required.
2. FIRECalc.com — Best for Historical Data
FIRECalc has been around since 2008 and uses historical stock market data going back to 1871 for its Monte Carlo simulations. It is extremely thorough, but the interface is dated and it does not support Lean/Fat FIRE mode toggles. Best for users who want deep historical analysis, not quick planning.
3. fire-calc.com — Best for Advanced Modeling
A newer entrant (early 2026) with an advanced calculator that models pre-retirement growth, tax-aware drawdown sequencing, and inflation-adjusted withdrawals. Strong for detailed financial modeling, but slightly more complex to use than basic calculators. All calculations run in-browser.
4. calculator.net — Best for Simple Estimates
The classic general-purpose calculator site includes a basic retirement/FIRE calculator. It is fast and covers the essentials, but lacks FIRE-specific modes (no Lean/Fat toggle), interactive charts, and educational content. Best for a quick, no-frills estimate. Note: calculations happen on their servers, not your browser.
5. firenum.com — Best for Deep FIRE Nerds
Firenum offers 8 different calculator modes including Lean, Fat, Coast, and Barista FIRE, plus Monte Carlo simulation and historical backtesting. The UI is clean and modern. A strong choice for users who want every scenario modeled — but the sheer number of options can be overwhelming for beginners.
6. myfirenumber.com — Best Open-Source Option
An open-source React + TypeScript project with 9 calculators, Recharts visualizations, and full PWA support. Great if you want to audit the code or self-host your own FIRE calculator. The UI is well-designed, though some calculators are more experimental than battle-tested.
7. coastfirecalc.io — Best for Coast FIRE
If you specifically want to calculate your Coast FIRE number — the amount you need saved so compound growth can carry you to retirement without further contributions — this is the best dedicated tool. It does not support other FIRE modes, but it does Coast FIRE better than anyone else.
8. theficalculator.com — Best for Barista FIRE
A clean, straightforward calculator with standard FIRE and Barista FIRE modes. The interface is simple to use, but it lacks charts and Lean/Fat toggles. Calculations run on their servers, so privacy-conscious users may prefer browser-based alternatives.
Which One Should You Choose?
- If you want the best overall experience with Lean/Regular/Fat modes and interactive charts, start with PlanFolio's FIRE Calculator.
- If you need historical backtesting and Monte Carlo, go with FIRECalc.com or firenum.com.
- If you want to inspect or modify the code, myfirenumber.com is open-source.
- If you only need Coast FIRE, use the dedicated coastfirecalc.io.
Ready to find your FIRE number?
Try PlanFolio's free FIRE calculator — Lean, Regular, and Fat modes in one tool.
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