WooCommerce: Force Max 1 Category Per Product

Here’s yet another snippet I use on A Piece of Sicily, my Sicilian marketplace, to make sure vendors can only select one product category for a given product. This is to make sure they make the best possible choice and also to avoid confusion and multiple listing.

Of course, the same can be used on your own WooCommerce install, in case you wish to limit the number of categories that can be assigned to each product (inside the snippet, you can even change “1” to “whatever number” and therefore define your own “max” e.g. max 2 categories).

This time I can’t make you “see” the customization as we’re in the backend, so please take a look at the screenshot below. Enjoy!

PHP Snippet: Force Max 1 Product Category Per Product @ Product Add/Edit Admin Page

/**
 * @snippet       Max 1 Product Cat @ Product Edit/Add Page
 * @how-to        Get CustomizeWoo.com FREE
 * @author        Rodolfo Melogli
 * @compatible    WooCommerce 5
 * @community     https://businessbloomer.com/club/
 */

add_action( 'admin_head', 'bbloomer_max_one_product_category', 9999 );

function bbloomer_max_one_product_category() {
	$screen = get_current_screen();
	$screen_id = $screen ? $screen->id : '';
	if ( ( 'add' === $screen->action && 'product' === $_GET['post_type'] ) || in_array( $screen_id, array( 'product', 'edit-product' ) ) ) {
		wc_enqueue_js( "
			$('#product_cat-all input:checkbox').change(function () {
				var max = 1;
				var count = $('#product_cat-all input:checked').length;
				if (count > max) {
					$(this).prop('checked', '');
					alert('Sorry, you can only pick one category. Please untick current category and pick another one in case you wish to switch category.');
				}
			});
		" );
	}
}

Where to add custom code?

You should place custom PHP in functions.php and custom CSS in style.css of your child theme: where to place WooCommerce customization?

This code still works, unless you report otherwise. To exclude conflicts, temporarily switch to the Storefront theme, disable all plugins except WooCommerce, and test the snippet again: WooCommerce troubleshooting 101

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Rodolfo Melogli

Business Bloomer Founder

Author, WooCommerce expert and WordCamp speaker, Rodolfo has worked as an independent WooCommerce freelancer since 2011. His goal is to help entrepreneurs and developers overcome their WooCommerce nightmares. Rodolfo loves travelling, chasing tennis & soccer balls and, of course, wood fired oven pizza. Follow @rmelogli