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!

Here’s what happens with the snippet below if you’re editing a product which has already a category assigned to it. Once you try to select a second category, an error message triggers and the second category is immediately unchecked.

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
 * @donate $9     https://businessbloomer.com/bloomer-armada/

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 this snippet?

You can place PHP snippets at the bottom of your child theme functions.php file (delete "?>" if you have it there). CSS, on the other hand, goes in your child theme style.css file. Make sure you know what you are doing when editing such files - if you need more guidance, please take a look at my free video tutorial "Where to Place WooCommerce Customization?"

Does this snippet (still) work?

Please let me know in the comments if everything worked as expected. I would be happy to revise the snippet if you report otherwise (please provide screenshots). I have tested this code with Storefront theme, the WooCommerce version listed above and a WordPress-friendly hosting on PHP 7.3.

If you think this code saved you time & money, feel free to join 14,000+ WooCommerce Weekly subscribers for blog post updates or 250+ Business Bloomer supporters for 365 days of WooCommerce benefits. Thank you in advance :)

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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.

2 thoughts on “WooCommerce: Force Max 1 Category Per Product

  1. That is cool snipet thanks! How about 1 per level ? I think will be more efficient for optimization,breadcrumbs and filters.

    1. Hi MArtin, thanks so much for your comment! Yes, this is definitely possible, but I’m afraid it’s custom work. If you’d like to get a quote, feel free to contact me here. Thanks a lot for your understanding!

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