Spright predicts planetary masses, densities, and radial velocity semi-amplitudes given a small planet's radius or planetary radii given the small planet's mass. The package contains two relations: one for small planets orbiting M dwarfs and another for planets orbiting FGK stars. The radial velocity semi-amplitude can be predicted given the planet's radius, orbital period, orbital eccentricity (optional), and the host star mass. Spright offers both a command line script and a set of Python classes. The command line script can directly create publication-quality plots, and the classes offer a full access to the predicted numerical distributions.