diff --git a/docs/reference/mapping/date-format.asciidoc b/docs/reference/mapping/date-format.asciidoc
index c2e4b6d8bbb..77df3d429dd 100644
--- a/docs/reference/mapping/date-format.asciidoc
+++ b/docs/reference/mapping/date-format.asciidoc
@@ -29,8 +29,8 @@ query/filter (mainly makes sense in `range` query/filter).
 The expression starts with an "anchor" date, which can be either `now`
 or a date string (in the applicable format) ending with `||`. It can
 then follow by a math expression, supporting `+`, `-` and `/`
-(rounding). The units supported are `y` (year), `M` (month), `w` (week), `h` (hour),
-`m` (minute), and `s` (second).
+(rounding). The units supported are `y` (year), `M` (month), `w` (week),
+`d` (day), `h` (hour), `m` (minute), and `s` (second).
 
 Here are some samples: `now+1h`, `now+1h+1m`, `now+1h/d`,
 `2012-01-01||+1M/d`.