diff --git a/src/calibre/ebooks/chardet.py b/src/calibre/ebooks/chardet.py
index f75b7915e1..22ef35eca2 100644
--- a/src/calibre/ebooks/chardet.py
+++ b/src/calibre/ebooks/chardet.py
@@ -73,8 +73,8 @@ def force_encoding(raw, verbose, assume_utf8=False):
     if chardet['confidence'] < 1 and assume_utf8:
         encoding = 'utf-8'
     if chardet['confidence'] < 1 and verbose:
-        print('WARNING: Encoding detection confidence %d%%'%(
-            chardet['confidence']*100))
+        print('WARNING: Encoding detection confidence for %s is %d%%'%(
+            chardet['encoding'], chardet['confidence']*100))
     if not encoding:
         encoding = preferred_encoding
     encoding = encoding.lower()