diff --git a/MagneticField/MagFieldElements/MagFieldElements/BFieldVector.h b/MagneticField/MagFieldElements/MagFieldElements/BFieldVector.h
index 2d1a79e57b11cabe0e6eb9b2acaa457f3c75e133..d689148e782bbf795c9f21489db102a65ed5c09a 100644
--- a/MagneticField/MagFieldElements/MagFieldElements/BFieldVector.h
+++ b/MagneticField/MagFieldElements/MagFieldElements/BFieldVector.h
@@ -16,6 +16,7 @@
 #define BFIELDVECTOR_H
 
 #include <array>
+#include <cstdlib>
 
 template<class T>
 class BFieldVector