The way you use to calculate the elapsed time is correct. You can use any of the various modules for date/time calculations to nicely format it in a human readable way.

Incidentally, almost by definitition, there's no need to create unnecessary temporary variable that are used once only:

my $sttime = time;
sleep(60);
print "Elapsed time : ", time - $sttime;
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Now, that is "simpler" - I also added a my, since you're use'ing strict anyway, don't you?
;-)