diff --git a/man8/zdump.8 b/man8/zdump.8
index d9e9d7e97..e00cb0d60 100644
--- a/man8/zdump.8
+++ b/man8/zdump.8
@@ -6,10 +6,14 @@ zdump \- timezone dumper
 .SH SYNOPSIS
 .B zdump
 [
+.B \-\-version
+] [
+.B \-\-help
+] [
 .B \-v
 ] [
 .B \-c
-cutoffyear ] [ zonename ... ]
+[loyear,]hiyear ] [ zonename ... ]
 .SH DESCRIPTION
 .I Zdump
 prints the current time in each
@@ -18,6 +22,12 @@ named on the command line.
 .PP
 These options are available:
 .TP
+.B \-\-version
+Output version information and exit.
+.TP
+.B \-\-help
+Output short usage and exit.
+.TP
 .B \-v
 For each
 .I zonename
@@ -34,8 +44,11 @@ if the given time is Daylight Saving Time or
 .B isdst=0
 otherwise.
 .TP
-.BI "\-c " cutoffyear
-Cut off the verbose output near the start of the given year.
+.BI "\-c " [loyear,]hiyear
+Cut off the verbose output near the start of the given year(s).
+The output still includes the lowest possible time value
+and one day after it, and the highest possible time value
+preceded by the time value one day before it.
 .SH "SEE ALSO"
 .BR tzfile (5),
 .BR zic (8)