This simple code applies the Helmholtz and wave–vortex decompositions developed in Bühler et al. (JFM, 2014) to given velocity and buoyancy wavenumber spectra. A Python (wvdec.py) and a MATLAB (wvdec.m) version of the code is provided. Both a hydrostatic and a nonhydrostatic version of the wave–vortex decomposition is given; if vertical velocity spectra are available, the nonhydrostatic version can be used, as in the example that is supplied with this code. Please refer to the Bühler et al. paper for a discussion of the assumptions going into the decomposition.