diff --git a/configuration.nix b/configuration.nix
index 0651763..fb3e84e 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -113,7 +113,7 @@ in
         ))
 
         inputs.kompas3d.packages.${pkgs.system}.default # KOMPAS-3D
-        freecad elmerfem gmsh # FEM calculation
+        freecad elmerfem calculix-ccx gmsh # FEM calculation
 
         inputs.stm32cubemx.packages.x86_64-linux.stm32cubemx