diff --git a/extract/extract.py b/extract/extract.py
index 973d4eb..93eca9b 100644
--- a/extract/extract.py
+++ b/extract/extract.py
@@ -133,7 +133,7 @@ class ExtractPlugin(PapersPlugin):
                         "\n", ""
                     )
                     if content:
-                        annotations.append(f"[{page.number}] {content}")
+                        annotations.append(f"[{(page.number or 0) + 1}] {content}")
         return annotations
 
     def _to_stdout(self, annotated_papers):