diff --git a/cps/constants.py b/cps/constants.py
index 89810e90..c1bcbe59 100644
--- a/cps/constants.py
+++ b/cps/constants.py
@@ -113,7 +113,8 @@ del env_CALIBRE_PORT
 
 
 EXTENSIONS_AUDIO    = {'mp3', 'mp4', 'ogg', 'opus', 'wav', 'flac', 'm4a', 'm4b'}
-EXTENSIONS_CONVERT  = ['pdf', 'epub', 'mobi', 'azw3', 'docx', 'rtf', 'fb2', 'lit', 'lrf', 'txt', 'htmlz', 'rtf', 'odt']
+EXTENSIONS_CONVERT_FROM  = ['pdf', 'epub', 'mobi', 'azw3', 'docx', 'rtf', 'fb2', 'lit', 'lrf', 'txt', 'htmlz', 'rtf', 'odt','cbz','cbr']
+EXTENSIONS_CONVERT_TO  = ['pdf', 'epub', 'mobi', 'azw3', 'docx', 'rtf', 'fb2', 'lit', 'lrf', 'txt', 'htmlz', 'rtf', 'odt']
 EXTENSIONS_UPLOAD   = {'txt', 'pdf', 'epub', 'kepub', 'mobi', 'azw', 'azw3', 'cbr', 'cbz', 'cbt', 'djvu', 'prc', 'doc', 'docx',
                        'fb2', 'html', 'rtf', 'lit', 'odt', 'mp3', 'mp4', 'ogg', 'opus', 'wav', 'flac', 'm4a', 'm4b'}
 
diff --git a/cps/editbooks.py b/cps/editbooks.py
index 7f7764e5..be9adc55 100644
--- a/cps/editbooks.py
+++ b/cps/editbooks.py
@@ -308,7 +308,7 @@ def render_edit_book(book_id):
     kepub_possible=None
     if config.config_converterpath:
         for file in book.data:
-            if file.format.lower() in constants.EXTENSIONS_CONVERT:
+            if file.format.lower() in constants.EXTENSIONS_CONVERT_FROM:
                 valid_source_formats.append(file.format.lower())
     if config.config_kepubifypath and 'epub' in [file.format.lower() for file in book.data]:
         kepub_possible = True
@@ -317,7 +317,7 @@ def render_edit_book(book_id):
 
     # Determine what formats don't already exist
     if config.config_converterpath:
-        allowed_conversion_formats = constants.EXTENSIONS_CONVERT[:]
+        allowed_conversion_formats = constants.EXTENSIONS_CONVERT_TO[:]
         for file in book.data:
             if file.format.lower() in allowed_conversion_formats:
                 allowed_conversion_formats.remove(file.format.lower())