The WIEN2k package is a computer program written in Fortran that performs quantum mechanical calculations on periodic solids.

It uses the full-potential (linearized) augmented plane-wave and local-orbitals [FP-(L)APW+lo] basis set to solve the Kohn–Sham equations of density functional theory.

WIEN2k was originally developed by Peter Blaha and Karlheinz Schwarz from the Institute of Materials Chemistry of the Vienna University of Technology.

It is based on the most accurate scheme for the calculation of the bond structure-the full potential energy (linear) augmented plane wave ((L) APW) + local orbit (lo) method.

It supports a variety of functionals including local-density approximation (LDA), many different generalized gradient approximations (GGA), Hubbard models, on-site hybrids, meta-GGA and full hybrids, and can also include spin-orbit coupling and Van der Waals terms.