Rydberg Equation Calculator

About this calculator

This calculator finds the wavelength of a hydrogen spectral line using the Rydberg equation: 1/λ = R · (1/n1² − 1/n2²), where R is the Rydberg constant and n1, n2 are the initial and final principal quantum (energy) levels of the electron. It explains the discrete lines seen in hydrogen's emission and absorption spectra, including the Lyman (UV), Balmer (visible), and Paschen (infrared) series depending on which level the electron ends at.

Chemistry and physics students use it to predict exactly which wavelengths hydrogen will emit or absorb when electrons jump between energy levels, connecting the abstract idea of quantized energy levels to real, measurable spectral lines seen with a spectroscope. Enter the two energy levels to get the wavelength.