diff --git a/Lib/filecmp.py b/Lib/filecmp.py
index cfdca1e924f552..44d498c802cfeb 100644
--- a/Lib/filecmp.py
+++ b/Lib/filecmp.py
@@ -12,12 +12,12 @@
 
 import os
 import stat
+from io import DEFAULT_BUFFER_SIZE as BUFSIZE
 from itertools import filterfalse
 
 __all__ = ['clear_cache', 'cmp', 'dircmp', 'cmpfiles', 'DEFAULT_IGNORES']
 
 _cache = {}
-BUFSIZE = 8*1024
 
 DEFAULT_IGNORES = [
     'RCS', 'CVS', 'tags', '.git', '.hg', '.bzr', '_darcs', '__pycache__']