ReynoldsNumberAssistant is an app designed for engineers, students, and hobbyists working with fluid flow. It helps calculate the Reynolds number quickly and accurately using inputs like velocity, pipe diameter, and fluid viscosity. The app includes handy tools for velocity and pipe diameter calculations, a reference tab with essential formulas and guidance, and a fluid properties section to look up common parameters. You can save calculations to a notebook, review your history, and organize notes for future projects. With a clean, modern interface and sensible defaults, it streamlines routine fluid mechanics tasks and supports consistent, error‑free engineering decisions.