ABCAP (All-electron Band-structure CAlculation Package) is the first principles electronic band structure calculation package using the FLAPW (Full-potential Linearized Augmented Plane Wave) method based on the density functional theory.

The FLAPW method is known as one of the most reliable methods without any shape approximations to potentials and has an advantage over a pseudopotential method in obtaining accurate electronic structures even for d- and f- electron systems.
ABCAP has succeeded in clarifying electronic and magnetic properties of many materials.