It is pretty common now for website owners and bloggers to tag their pages to help search engines better index them and to make them easier to navigate for readers. It’s perfectly acceptable to do this. But is there a limit to how many tags you can use on one page?
I don’t know of any technical limit on tags, but I would caution you against using too many tags on a single page.
First, I would make sure that every tag you do use for a page on your website is relevant to that page. DO NOT try to add a tag that is not relevant to the page. If you do that, then you run the risk of your page not being indexed.
I would also stay away from using multiple singular and plural forms of words as tags. If you use 20 tags on one page that are essentially 10 tags with singular and plural forms of each, that won’t look good to the search engines. You are better off using either the singular or the plural for each keyword tag.
I think the most optimal number of tags for a single page is somewhere between 3 and 7. I wouldn’t say that all of your pages should have the same number of tags. That might be going too far. But if you only have one or two tags per page, then you probably aren’t tagging enough. Similarly, if all of your pages have more than 7 tags, then you may be tagging too much. You can go over or under for individual pages, but don’t make a habit of over-tagging or under-tagging. You want to keep your website clean.