diff --git a/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp b/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp
index 91aa1bc0..0ef0daa4 100644
--- a/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp
+++ b/libs/qsynedit/qsynedit/exporter/rtfexporter.cpp
@@ -145,7 +145,11 @@ QString RTFExporter::getFormatName()
 QString RTFExporter::getHeader()
 {
     QFontMetrics fm(mFont);
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)    
     int tabWidth = mTabSize * fm.horizontalAdvance("M")*72*20/fm.fontDpi();
+#else  
+    int tabWidth = mTabSize * fm.horizontalAdvance("M")*72*20/96;
+#endif
 
     QString result = QString("{\\rtf1\\ansi\\deff0\\deftab%1").arg(tabWidth) + getFontTable();
     // all the colors