diff --git a/src/libcalamares/utils/CalamaresUtilsSystem.cpp b/src/libcalamares/utils/CalamaresUtilsSystem.cpp
index 9a4ba990f..a2ba51ded 100644
--- a/src/libcalamares/utils/CalamaresUtilsSystem.cpp
+++ b/src/libcalamares/utils/CalamaresUtilsSystem.cpp
@@ -230,7 +230,7 @@ System::createTargetParentDirs( const QString& filePath ) const
 }
 
 
-QPair< quint64, float >
+QPair< qint64, qreal >
 System::getTotalMemoryB() const
 {
 #ifdef Q_OS_LINUX
diff --git a/src/libcalamares/utils/CalamaresUtilsSystem.h b/src/libcalamares/utils/CalamaresUtilsSystem.h
index 1bb5629d1..f7f04079e 100644
--- a/src/libcalamares/utils/CalamaresUtilsSystem.h
+++ b/src/libcalamares/utils/CalamaresUtilsSystem.h
@@ -337,7 +337,7 @@ public:
      *
      * @return size, guesstimate-factor
      */
-    DLLEXPORT QPair< quint64, float > getTotalMemoryB() const;
+    DLLEXPORT QPair< qint64, qreal > getTotalMemoryB() const;
 
     /**
      * @brief getCpuDescription returns a string describing the CPU.