diff --git a/src/calibre/ebooks/oeb/polish/check/main.py b/src/calibre/ebooks/oeb/polish/check/main.py
index fe6e5b1e28..dd7fdc6092 100644
--- a/src/calibre/ebooks/oeb/polish/check/main.py
+++ b/src/calibre/ebooks/oeb/polish/check/main.py
@@ -61,7 +61,8 @@ def run_checks(container):
             items = raster_images
         if items is not None:
             items.append((name, mt, container.raw_data(name, decode=decode)))
-    errors.extend(run_checkers(check_html_size, html_items))
+    if container.book_type == 'epub':
+        errors.extend(run_checkers(check_html_size, html_items))
     errors.extend(run_checkers(check_xml_parsing, xml_items))
     errors.extend(run_checkers(check_xml_parsing, html_items))
     errors.extend(run_checkers(check_raster_images, raster_images))