diff --git a/kindlecomicconverter/comic2ebook.py b/kindlecomicconverter/comic2ebook.py
index 39a7f19..469812a 100755
--- a/kindlecomicconverter/comic2ebook.py
+++ b/kindlecomicconverter/comic2ebook.py
@@ -1933,8 +1933,11 @@ def makeMOBIWorker(item):
     kindlegenError = ''
     try:
         if os.path.getsize(item) < 629145600:
+            start = perf_counter()
             output = subprocess_run(['kindlegen', '-dont_append_source', '-locale', 'en', item],
                            stdout=PIPE, stderr=STDOUT, encoding='UTF-8', errors='ignore', check=True)
+            end = perf_counter()
+            print(f"kindlegen: {end - start} sec")
         else:
             # ERROR: EPUB too big
             kindlegenErrorCode = 23026