Index: src/render/katerenderer.h
===================================================================
--- src/render/katerenderer.h
+++ src/render/katerenderer.h
@@ -237,8 +237,8 @@
     /**
      * Change to a different font (soon to be font set?)
      */
-    void increaseFontSizes();
-    void decreaseFontSizes();
+    void increaseFontSizes(qreal step = 1.0);
+    void decreaseFontSizes(qreal step = 1.0);
     const QFont &currentFont() const;
     const QFontMetricsF &currentFontMetrics() const;
 
Index: src/render/katerenderer.cpp
===================================================================
--- src/render/katerenderer.cpp
+++ src/render/katerenderer.cpp
@@ -143,20 +143,20 @@
     m_showSelections = showSelections;
 }
 
-void KateRenderer::increaseFontSizes()
+void KateRenderer::increaseFontSizes(qreal step)
 {
     QFont f(config()->font());
-    f.setPointSize(f.pointSize() + 1);
+    f.setPointSizeF(f.pointSizeF() + step);
 
     config()->setFont(f);
 }
 
-void KateRenderer::decreaseFontSizes()
+void KateRenderer::decreaseFontSizes(qreal step)
 {
     QFont f(config()->font());
 
-    if ((f.pointSize() - 1) > 0) {
-        f.setPointSize(f.pointSize() - 1);
+    if ((f.pointSizeF() - step) > 0) {
+        f.setPointSizeF(f.pointSizeF() - step);
     }
 
     config()->setFont(f);
Index: src/view/kateviewinternal.h
===================================================================
--- src/view/kateviewinternal.h
+++ src/view/kateviewinternal.h
@@ -149,8 +149,8 @@
     void dynWrapChanged();
 
 public Q_SLOTS:
-    void slotIncFontSizes();
-    void slotDecFontSizes();
+    void slotIncFontSizes(qreal step = 1.0);
+    void slotDecFontSizes(qreal step = 1.0);
 
     void paintCursor();
 
Index: src/view/kateviewinternal.cpp
===================================================================
--- src/view/kateviewinternal.cpp
+++ src/view/kateviewinternal.cpp
@@ -335,14 +335,14 @@
     return (viewLine - startLine()) * renderer()->lineHeight();
 }
 
-void KateViewInternal::slotIncFontSizes()
+void KateViewInternal::slotIncFontSizes(qreal step)
 {
-    renderer()->increaseFontSizes();
+    renderer()->increaseFontSizes(step);
 }
 
-void KateViewInternal::slotDecFontSizes()
+void KateViewInternal::slotDecFontSizes(qreal step)
 {
-    renderer()->decreaseFontSizes();
+    renderer()->decreaseFontSizes(step);
 }
 
 /**
@@ -3298,9 +3298,9 @@
     // ctrl pressed -> change font size (only if angle is reported)
     if (e->modifiers() == Qt::ControlModifier) {
         if (e->angleDelta().y() > 0) {
-            slotIncFontSizes();
+            slotIncFontSizes(qreal(e->angleDelta().y()) / QWheelEvent::DefaultDeltasPerStep);
         } else if (e->angleDelta().y() < 0) {
-            slotDecFontSizes();
+            slotDecFontSizes(qreal(-e->angleDelta().y()) / QWheelEvent::DefaultDeltasPerStep);
         }
 
         // accept always and be done for zooming