BigDFT is a free software package for physicists and chemists, distributed under the GNU General Public License, whose main program allows the total energy, charge density, and electronic structure of systems made of electrons and nuclei (molecules and periodic/crystalline solids) to be calculated within density functional theory (DFT), using pseudopotentials, and a wavelet basis.

[1] BigDFT implements density functional theory (DFT) by solving the Kohn–Sham equations describing the electrons in a material, expanded in a Daubechies wavelet basis set and using a self-consistent direct minimization or Davidson diagonalisation methods to determine the energy minimum.

In addition to total energy, forces and stresses are also calculated so that geometry optimizations and ab initio molecular dynamics may be carried out.

Interpolating scaling functions are used also to solve the Poisson's equation[2][3] with different boundary conditions as isolated or surface systems.

BigDFT was among the first massively parallel density functional theory codes which benefited from graphics processing units (GPU)[4] using CUDA and then OpenCL languages.