Snippet: TagCloud With Different Font Sizes

add_filter( 'widget_tag_cloud_args', function( $args ) {
	$args['largest']  = '0.923'; // add your custom largest size here
	$args['smallest'] = '0.923'; // Add your custom smallest size here
	$args['unit']     = 'em';    // You can choose between em or px values
	return $args;
}, 40 );