Show HN: A private FIRE calculator suite that runs in the browser

3 points by Mikulas_Tomanka 5 hours ago

Hi HN,

I built Firenum because most FIRE calculators I found were either too simplistic or required uploading my entire financial life to a third-party server.

I wanted a comprehensive suite that could model more than just the 4% rule. This tool handles Coast, Lean, Fat, and Barista FIRE, but more importantly, it lets you model 'what-if' scenarios like market crashes or major life events to see how they impact your timeline.

Key features:

-> Privacy-First: No signup required. All calculations and data persistence happen in your local storage. Nothing is sent to a backend.

-> Scenario Modeling: You can simulate market downturns to see the resilience of your plan.

-> Multi-Currency: Supports 8 major currencies.

-> Progress Tracking: A dashboard to visualize the 'boring middle' of the journey.

The goal was to make something as powerful as a complex spreadsheet but with a much better UX. I’d love to hear your thoughts on the projection logic and if there are any specific variables (like tax drag or inflation adjustments) you think are missing.

URL: https://firenum.com/

I’m happy to answer any questions about the math or the local-first implementation!