diff --git a/electrum/gui/qt/qrcodewidget.py b/electrum/gui/qt/qrcodewidget.py
index c8f84934b..7f1959fa7 100644
--- a/electrum/gui/qt/qrcodewidget.py
+++ b/electrum/gui/qt/qrcodewidget.py
@@ -85,7 +85,8 @@ class QRCodeWidget(QWidget):
         for r in range(k):
             for c in range(k):
                 if matrix[r][c]:
-                    qp.drawRect(left+c*boxsize, top+r*boxsize, boxsize - 1, boxsize - 1)
+                    qp.drawRect(int(left+c*boxsize), int(top+r*boxsize),
+                                boxsize - 1, boxsize - 1)
         qp.end()