I think you want scalar instead of length. This prints 3: 
use warnings;
use strict;

my $hashref = {
          'x' => 0,
          'y' => 0,
          'zzz' => 0
        };
print scalar keys %$hashref;

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In reply to Re: Wrong result for "length keys %$hashref"? by toolic
in thread Wrong result for "length keys %$hashref"? by samwyse

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