This interactive real estate ROI calculator evaluates a specific property at 1826 Brookview Road in Castleton On Hudson, NY, displaying key financial metrics such as monthly cash flow, cap rate, and cash-on-cash ROI. Users adjust property details, financing, and expense inputs through a form, which triggers real-time recalculations. The results panel visualizes monthly cash flow components as a bar chart and projects ten years of investment performance with D3.js line charts, with interactive tooltips and toggleable metrics. Built with React, SVG, and D3.js v7, the interface supports tabbed views for cash flow, projections, and a detailed summary table.