  We present a python package to calculate interaction rates of light dark
matter in dielectric materials, including screening effects. The full response
of the material is parametrized in the terms of the energy loss function (ELF)
of material, which darkELF converts into differential scattering rates for both
direct dark matter electron scattering and through the Migdal effect. In
addition, darkELF can calculate the rate to produce phonons from sub-MeV dark
matter scattering via the dark photon mediator, as well as the absorption rate
for dark matter comprised of dark photons. The package includes precomputed
ELFs for Al, $\mathrm{Al}_2\mathrm{O}_3$, GaAs, GaN, Ge, Si, $\mathrm{SiO}_2$,
and ZnS, and allows the user to easily add their own ELF extractions for
arbitrary materials.
