CircuVerne is a one-of-a-kind photonics calculator that bridges theory and practice by focusing on the Vernier effect in coupled optical ring resonators. Unlike generic scientific tools, it is tailored to handle wavelength-scale parameters and free spectral range calculations with precision, providing not just raw numbers but also meaningful interpretations of how ring radii ratios influence tuning performance. Its intuitive interface with gradient visuals, guided input validation, and contextual tips makes complex optical concepts accessible on a mobile device, empowering students, engineers, and researchers to explore resonator behavior quickly and confidently in real time.