Hyphens vs. Underscores in URLs: What Google Prefers in 2026

In the world of SEO, the smallest details often make the biggest difference. One debate that has persisted among developers and digital marketers for years is whether to use hyphens (-) or underscores (_) as word separators in URL slugs.

While it might seem trivial, how you separate words in your URLs directly impacts how search engines crawl, index, and rank your content.

The Technical Difference

To understand the preference, we have to look at how search engine algorithms—specifically Google's—interpret these characters.

• Hyphens (the "Separator"): Google treats hyphens as spaces. If your URL is clean-text-labs, Google sees three distinct words: "clean", "text", and "labs". This allows your page to rank for each individual keyword.
• Underscores (the "Joiner"): Historically, Google treats underscores as word joiners. If your URL is clean_text_labs, search engines may interpret this as a single, unique term: "cleantextlabs".

Why Google Prefers Hyphens

Google's official documentation and representatives (like John Mueller) have consistently recommended hyphens over underscores for years. In 2026, this remains the industry standard.

When you use hyphens, you are effectively "explaining" the structure of your content to the crawler. It makes it easier for the algorithm to identify the keywords in your URL slug, which is a significant ranking factor for SEO-friendly URLs.

What About Existing Underscores?

If you already have a site full of underscores, don't panic. While hyphens are better, Google is smart enough to eventually figure out the content of a page. However, for new content, you should always stick to hyphens.

Changing established URLs with underscores can actually hurt your SEO temporarily if you don't implement proper 301 redirects, so it's often best to simply use hyphens for everything moving forward.

Automating Your URL Structure

Manually typing out SEO-friendly slugs can be error-prone. You might accidentally leave an uppercase letter (which can cause duplicate content issues) or forget a separator.

That’s why we built our Free SEO Slug Generator. It automatically takes any title, removes special characters, converts everything to lowercase, and—most importantly—uses hyphens to ensure your URLs are perfectly optimized for Google's latest standards.