Change content area box size

Just add this code to your functions.php and its done.You can change the size 500px to any……….

<?php

function reduce_editor_height() {
    echo '<style>
        #postdivrich {
            max-height: xxpx; /* Reduce content editor height */
            overflow-y: auto;
        }
    </style>';
}
add_action('admin_head', 'reduce_editor_height');