It's impossible to know the different in minutes without knowing the timezone of the times.

I use DateTime

#!/usr/bin/perl

use strict;
use warnings;

use DateTime                   qw( );
use DateTime::Format::Strptime qw( );

my $format = DateTime::Format::Strptime->new(
    pattern => '%Y-%m-%d %H:%M:%S',
);

my $start = $format->parse_datetime( '2007-12-31 16:50:00' );
my $stop  = $format->parse_datetime( '2008-1-1 04:24:00' );

$_->set_time_zone('local') for $start, $stop;

print( $start->delta_ms($stop)->in_units('minutes'), "\n" );  # 694
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