diff --git a/src/Base/UnitsSchemaInternal.cpp b/src/Base/UnitsSchemaInternal.cpp
index fcdb4b3f49..f00be684e3 100644
--- a/src/Base/UnitsSchemaInternal.cpp
+++ b/src/Base/UnitsSchemaInternal.cpp
@@ -29,6 +29,7 @@
 #include <QString>
 
 #include "UnitsSchemaInternal.h"
+#include <cmath>
 
 
 using namespace Base;
diff --git a/src/Base/UnitsSchemaMKS.cpp b/src/Base/UnitsSchemaMKS.cpp
index 669d4dea9d..2bb0f9ab40 100644
--- a/src/Base/UnitsSchemaMKS.cpp
+++ b/src/Base/UnitsSchemaMKS.cpp
@@ -29,6 +29,7 @@
 #include <QString>
 
 #include "UnitsSchemaMKS.h"
+#include <cmath>
 
 
 using namespace Base;