diff --git a/src/calibre/gui2/dialogs/metadata_bulk.py b/src/calibre/gui2/dialogs/metadata_bulk.py
index 02bc05b20c..a778a67797 100644
--- a/src/calibre/gui2/dialogs/metadata_bulk.py
+++ b/src/calibre/gui2/dialogs/metadata_bulk.py
@@ -925,7 +925,7 @@ class MetadataBulkDialog(ResizableDialog, Ui_MetadataBulkDialog):
             self.series_numbering_restarts.setEnabled(False)
             self.series_numbering_restarts.setChecked(False)
             self.series_start_number.setEnabled(False)
-            self.series_start_number.setValue(1)
+            self.series_start_number.setValue(1.0)
 
     def reject(self):
         self.save_state()
diff --git a/src/calibre/gui2/dialogs/metadata_bulk.ui b/src/calibre/gui2/dialogs/metadata_bulk.ui
index 277a9374d9..e54e27c28b 100644
--- a/src/calibre/gui2/dialogs/metadata_bulk.ui
+++ b/src/calibre/gui2/dialogs/metadata_bulk.ui
@@ -386,18 +386,18 @@ from the value in the box</string>
               </widget>
              </item>
              <item>
-              <widget class="QSpinBox" name="series_start_number">
+              <widget class="QDoubleSpinBox" name="series_start_number">
                <property name="enabled">
                 <bool>false</bool>
                </property>
                <property name="minimum">
-                <number>1</number>
+                <double>1.000000000000000</double>
                </property>
                <property name="maximum">
-                <number>99000000</number>
+                <double>99000000.000000000000000</double>
                </property>
                <property name="value">
-                <number>1</number>
+                <double>1.000000000000000</double>
                </property>
               </widget>
              </item>