diff --git a/src/pkg/fmt/doc.go b/src/pkg/fmt/doc.go
index 03800aa47a8..b717b7f2793 100644
--- a/src/pkg/fmt/doc.go
+++ b/src/pkg/fmt/doc.go
@@ -16,6 +16,7 @@
 			when printing structs, the plus flag (%+v) adds field names
 		%#v	a Go-syntax representation of the value
 		%T	a Go-syntax representation of the type of the value
+		%%	a literal percent sign; consumes no value
 
 	Boolean:
 		%t	the word true or false