diff --git a/mercurial/helptext/config.txt b/mercurial/helptext/config.txt
--- a/mercurial/helptext/config.txt
+++ b/mercurial/helptext/config.txt
@@ -2630,7 +2630,8 @@
 ``large-file-limit``
     Largest file size that gives no memory use warning.
     Possible values are integers or 0 to disable the check.
-    (default: 10000000)
+    Value is expressed in bytes by default, one can use standard unit for
+    convenience (e.g. 10MB, 0.1GB, etc) (default: 10000000)
 
 ``logtemplate``
     (DEPRECATED) Use ``command-templates.log`` instead.