Circular dichroism (CD) spectroscopy is a highly used method for the examination and characterization of proteins, including, amongst other features, their secondary and tertiary structures, thermal stability, comparisons of wildtype and mutant proteins, and monitoring the binding of small molecules, folding/unfolding pathways, and formation of macromolecular complexes. This article describes CDtoolX, a new, user‐friendly, free‐to‐download‐and‐use software program that enables processing, displaying, archiving, calibrating, comparisons, and analyses of CD and synchrotron radiation circular dichroism spectroscopic data.