Fire Tools is a collection of free financial calculators designed to help you make smarter money decisions. Unlike generic calculators that give you a single number, our tools show you the full picture: probabilities, trade-offs, and the assumptions behind the math.
Most financial calculators online are either too simplistic (ignoring important factors like taxes and inflation) or too complicated (requiring a finance degree to understand). We wanted something in between: tools that are easy to use but don't oversimplify the math.
Every calculator on this site is built with real-world accuracy in mind. Our FIRE calculator uses Monte Carlo simulation instead of assuming average returns. Our rent vs buy calculator accounts for the opportunity cost of your down payment. Our side hustle tracker includes self-employment taxes that most people forget about.
All calculations happen in your browser. We don't store your financial data on any server. Your numbers stay on your device.
The tools and content on this site are for informational and educational purposes only. They should not be considered financial, investment, or tax advice. Everyone's financial situation is unique, and you should consult with qualified professionals before making significant financial decisions.