diff --git a/pysrt/commands.py b/pysrt/commands.py
index b2bfa24..9b7ede2 100755
--- a/pysrt/commands.py
+++ b/pysrt/commands.py
@@ -178,8 +178,11 @@ def split(self):
 
     def create_backup(self):
         backup_file = self.arguments.file + self.BACKUP_EXTENSION
-        if not os.path.exists(backup_file):
-            shutil.copy2(self.arguments.file, backup_file)
+        backup_idx = 1
+        while os.path.exists(backup_file):
+            backup_file = self.arguments.file + ('.%i' % backup_idx) + self.BACKUP_EXTENSION
+            backup_idx += 1
+        shutil.copy2(self.arguments.file, backup_file)
         self.output_file_path = self.arguments.file
         self.arguments.file = backup_file