diff --git a/composite.cpp b/composite.cpp
index f28aba7f9c..aa0e4b7286 100644
--- a/composite.cpp
+++ b/composite.cpp
@@ -79,7 +79,7 @@ void CompositorSelectionOwner::looseOwnership()
 
 KWIN_SINGLETON_FACTORY_VARIABLE(Compositor, s_compositor)
 
-static inline qint64 milliToNano(int milli) { return milli * 1000 * 1000; }
+static inline qint64 milliToNano(int milli) { return qint64(milli) * 1000 * 1000; }
 static inline qint64 nanoToMilli(int nano) { return nano / (1000*1000); }
 
 Compositor::Compositor(QObject* workspace)