codz.ai
free financial tools, mortgage, retirement, budget, networth
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Matt E

codz.ai - free financial tools, mortgage, retirement, budget, networth

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8 free financial tools I built for personal use and use daily. Mortgage calculator with extra payment modeling, compound interest with growth charts, Monte Carlo retirement simulator (10,000 trials), budget tracker with 50/30/20, net worth dashboard, rental property ROI analyzer, property manager with Schedule E, and time tracking with invoicing. All free, no ads. Calculators work without an account.

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Matt E
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I'm a full-stack engineer who started building these for myself — a mortgage calculator to model extra payments, a retirement simulator to stress-test my early retirement plan, and a budget tracker. Over time it grew into 8 tools. The calculators (mortgage, compound, retirement, ROI) work without signing in. The tracking tools (budget, net worth, rentals, invoicing) use Google sign-in to save your data. Built with React, Next.js, Supabase (Postgres + auth), and Chart.js. All 8 apps share one Supabase project for single sign-on across subdomains. Happy to answer questions about the financial math or architecture!