How to count the number of terms in a taxonomy

I have a custom post type “Services”. It has a hierarchal taxonomy of “service-category”. Service-category has both parent and child terms.

I need to count the number of parent terms in the taxonomy. NOT posts. The # of terms in the taxonomy is being used in my code to layout the page in a recursive loop.

Everything I have researched is about the number of posts per term, not the number of terms in the taxonomy.. I am sure I am missing an obvious way of doing this, but I haven’t run across it.

Thanks in advance for your help!

As @shanebp suggests, you could use wp_count_terms() like this:

$numTerms = wp_count_terms( 'service-category', array(
    'hide_empty'=> false,
    'parent'    => 0
) );

The above will list All top parent terms, empty or not. This function uses get_terms() functions arguments which can be found in the link or the arguments below:

$args = array(
    'orderby'           => 'name', 
    'order'             => 'ASC',
    'hide_empty'        => true, 
    'exclude'           => array(), 
    'exclude_tree'      => array(), 
    'include'           => array(),
    'number'            => '', 
    'fields'            => 'all', 
    'slug'              => '', 
    'parent'            => '',
    'hierarchical'      => true, 
    'child_of'          => 0, 
    'get'               => '', 
    'name__like'        => '',
    'description__like' => '',
    'pad_counts'        => false, 
    'offset'            => '', 
    'search'            => '', 
    'cache_domain'      => 'core'
);