diff --git a/src/cmd/gofmt/doc.go b/src/cmd/gofmt/doc.go
index a552d4cde4..13994fdeec 100644
--- a/src/cmd/gofmt/doc.go
+++ b/src/cmd/gofmt/doc.go
@@ -4,7 +4,10 @@
 
 /*
 Gofmt formats Go programs.
-It uses tabs (width = 8) for indentation and blanks for alignment.
+It uses tabs for indentation and blanks for alignment.
+
+Alignment assumes that an editor is using a fixed-width
+font and that a tab corresponds to 8 spaces.
 
 Without an explicit path, it processes the standard input.  Given a file,
 it operates on that file; given a directory, it operates on all .go files in