diff --git a/simplegmail/gmail.py b/simplegmail/gmail.py
index 2c9aba7..4446b1c 100644
--- a/simplegmail/gmail.py
+++ b/simplegmail/gmail.py
@@ -66,6 +66,7 @@ def __init__(
     ) -> None:
         self.client_secret_file = client_secret_file
         self.creds_file = creds_file
+        self._resultSizeEstimate = 0
 
         try:
             # The file gmail_token.json stores the user's access and refresh
@@ -516,6 +517,9 @@ def get_messages(
                 includeSpamTrash=include_spam_trash
             ).execute()
 
+            if 'resultSizeEstimate' in response:
+                self._resultSizeEstimate = response['resultSizeEstimate']
+
             message_refs = []
             if 'messages' in response:  # ensure request was successful
                 message_refs.extend(response['messages'])
@@ -530,6 +534,9 @@ def get_messages(
                     pageToken=page_token
                 ).execute()
 
+                if 'resultSizeEstimate' in response:
+                    self._resultSizeEstimate = response['resultSizeEstimate']
+
                 message_refs.extend(response['messages'])
 
             return self._get_messages_from_refs(user_id, message_refs,
@@ -988,3 +995,7 @@ def _get_alias_info(
 
         res = req.execute()
         return res
+
+    @property
+    def resultSizeEstimate(self):
+        return self._resultSizeEstimate