diff --git a/docs/honk.5 b/docs/honk.5
index 54fa3eb..c9609e1 100644
--- a/docs/honk.5
+++ b/docs/honk.5
@@ -106,6 +106,12 @@ accuracy.
 Pressing the check in button a second time will refine this to more a
 precise location.
 .Pp
+Adding a time to a post turns it into an event.
+Supported formats for start time are HH:MM or YYYY-MM-DD HH:MM.
+A 24 hour clock is assumed, unless am or pm are specified.
+The duration is optional and may be specified as XdYhZm for X days, Y hours,
+and Z minutes (1d12h would be a 36 hour event).
+.Pp
 When everything is at last ready to go, press the
 .Dq it's gonna be honked
 button.