Hyphens vs. Underscores in URLs: What Google Prefers in 2026
By M Nouman Saeed · Published on April 21, 2026 · Updated July 28, 2026 · 6 min read
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.
💡 Pro-Tip: Validate Your Inputs
Before generating URL slugs, make sure your text is free of hidden characters and extra spaces. You can use our Free Text Cleaner Tool to sanitize titles before creating slugs.
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".
| URL Style | How Google Reads It |
|---|---|
| /clean-text-online | clean, text, online (3 keywords) |
| /clean_text_online | cleantextonline (1 combined term) |
| /cleantextonline | cleantextonline (1 combined term) |
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 — a minor but easy-to-get-right piece of making a URL genuinely SEO-friendly.
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. If you do decide to migrate old URLs, do it in batches, set up redirects for every changed URL, and resubmit an updated sitemap so search engines can recrawl the new structure quickly.
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. For a full breakdown of slug best practices beyond just separators, see what a URL slug is and why it matters for SEO.
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.
Frequently Asked Questions
Will using underscores get my page penalized by Google?
No, it won't cause a penalty. Google can still crawl, index, and rank pages with underscores in the URL. The downside is more subtle: your page may not rank as precisely for individual keyword phrases, since underscore-joined words can be read as one combined term instead of separate keywords.
Should I use hyphens in filenames too, like images?
Yes. The same logic applies to image filenames. 'red-running-shoes.jpg' helps Google Images understand the content better than 'red_running_shoes.jpg' or 'IMG_4021.jpg'.
What about camelCase URLs, like /myBlogPost?
Avoid camelCase in URLs. Some servers treat URLs as case-sensitive, so '/myBlogPost' and '/myblogpost' could technically be seen as two different pages, risking duplicate content issues. Hyphenated lowercase URLs sidestep this entirely.
Do hyphens matter for subdomains too?
Subdomains follow different DNS rules and generally shouldn't use hyphens at the start or end of a label, but within a path (after the domain), the hyphen-for-spaces rule applies the same way it does for any other URL segment.
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