The Time::Duration module has the functionality you need. For example,

#!/usr/bin/env perl

use strict;
use warnings;

use Time::Piece;
use Time::Duration;

my $date_format = '%Y-%m-%d';

my $hiredate = Time::Piece->strptime('2014-05-05', $date_format );
my $nowdate = Time::Piece->strptime('2016-04-15', $date_format );

my $elapsed_seconds = $nowdate - $hiredate;

print "     Hire Date: $hiredate\n";
print "      Now Date: $nowdate\n";
print "It has been ", duration($elapsed_seconds), " since you were hir
+ed.\n";

exit;
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See Is there a CPAN module for converting seconds to English? for a helpful discussion on this topic.