diff --git a/usr.bin/du/du.1 b/usr.bin/du/du.1
index 1eb3fd0d9423..b6df798fd4a6 100644
--- a/usr.bin/du/du.1
+++ b/usr.bin/du/du.1
@@ -124,7 +124,8 @@ If the environment variable
 .Ev BLOCKSIZE
 is set, and the
 .Fl k
-option is not specified, the block counts will be displayed in 1024-byte blocks.
+option is not specified, the block counts will be displayed in units of that
+size block.
 If
 .Ev BLOCKSIZE
 is not set, and the