OptiVern is a specialized calculator that streamlines the study of coupled optical ring resonators by combining precise scientific models with an intuitive mobile design. It enables users to determine free spectral ranges, Vernier FSR, resonance shift factors, and optical losses, while also offering an advanced feature that calculates the optimal radius mismatch needed to achieve custom sensing enhancements. By condensing complex photonics equations into an accessible format, OptiVern delivers both accuracy and usability, making it a valuable companion for researchers, engineers, and students working with resonance-based optical systems.