LaSaturo is a dedicated laser physics utility that simplifies the calculation of saturation fluence, a critical parameter for Q-switched and pulsed laser systems. By combining a sleek gradient-based interface with accurate scientific computation, the app allows users to input photon energy and emission cross-section values and instantly obtain Fsat in J/cm². It goes beyond a basic calculator by offering input validation, clipboard-ready results, and an integrated reference guide that explains the formula, typical ranges, and worked examples, making it a reliable companion for photonics researchers, optical engineers, and students working with gain media and laser design.