diff --git a/kcm/src/scalingconfig.h b/kcm/src/scalingconfig.h
--- a/kcm/src/scalingconfig.h
+++ b/kcm/src/scalingconfig.h
@@ -38,7 +38,7 @@
 private:
     void load();
     qreal scaleFactor() const;
-    qreal scaleDPI() const;
+    int scaleDPI() const;
     Ui::Scaling ui;
     qreal m_initialScalingFactor = 1.0;
     KScreen::OutputList m_outputList;
diff --git a/kcm/src/scalingconfig.cpp b/kcm/src/scalingconfig.cpp
--- a/kcm/src/scalingconfig.cpp
+++ b/kcm/src/scalingconfig.cpp
@@ -119,9 +119,9 @@
     QDialog::accept();
 }
 
-qreal ScalingConfig::scaleDPI() const
+int ScalingConfig::scaleDPI() const
 {
-    return scaleFactor() * 96.0;
+    return qRound(scaleFactor()) * 96.0;
 }
 
 qreal ScalingConfig::scaleFactor() const