comment counter

Yes.

What might that be?

There is no need of plugin for showing comments count. Use the following code just in your posts listing loop or single page template to show the comments count:

<?php  comments_number('0', '1 comment', '% comments'); ?>

For more reference: https://codex.www.ads-software.com/Function_Reference/comments_number

thank you for your help but I’m a bit of a newbie and would prefer a plugin — thx

chandanonline4u’s suggestion is easy to implement.

but if you prefer a plugin, try this one: https://www.ads-software.com/extend/plugins/gregs-show-total-conversations/screenshots/