| name | hyphens |
| description | Use when auditing URL structures for word separator format, generating slugs from titles, or planning a URL migration from underscores or spaces to hyphens with appropriate redirects. |
| metadata | {"category":"seo","priority":"medium","difficulty":"intermediate","estimatedTime":"10","source":"frontendchecklist.io","url":"https://frontendchecklist.io/en/rules/seo/hyphens"} |
Use hyphens in URLs
Google's search systems interpret hyphens in URLs as word boundaries, enabling it to match the URL against individual keyword queries. Underscores join words into a single token, meaning /seo_practices is seen as one word 'seopractices' rather than two separate words 'seo' and 'practices'.
Quick Reference
- Use hyphens (
-) to separate words in URLs — Google treats hyphens as word separators, underscores as part of the word
/best-seo-practices is better than /best_seo_practices or /bestseopractices- Changing existing URLs from underscores to hyphens requires 301 redirects to preserve link equity
Check
Inspect the URL path segment of each page. Flag any URL that contains: (1) Underscores (_) as word separators (e.g., /best_practices). (2) Spaces encoded as %20 or + in path segments. (3) Mixed separators in the same URL (e.g., /best-practices_guide). Report the count of non-hyphenated URLs by category.
Fix
- Identify all pages with underscores or spaces in URL path segments.
- Generate the hyphenated equivalent: replace
_ with -, spaces/%20 with -.
- Set up 301 permanent redirects from the old URLs to the new hyphenated URLs.
- Update internal links throughout the site to point to the new URLs.
- Submit the new URLs to Google Search Console for re-indexing.
- Update your sitemap.xml to include only the new hyphenated URLs.
- In your CMS or slug-generation function, enforce hyphens going forward:
- Slug: title.toLowerCase().replace(/\s+/g, '-').replace(/[^a-z0-9-]/g, '')
Explain
Google's John Mueller has confirmed that Google interprets hyphens as word separators in URLs, but treats underscores as word joiners. This means a URL with underscores matches fewer individual keyword queries. For example, /web_design would match 'web_design' as a single token, while /web-design matches both 'web design' and 'webdesign' queries.
Code Review
Parse all URL paths used in the application's router or CMS slug fields. Flag any path segment containing _ characters between words or any %20 space encoding. Verify slug-generation utilities produce lowercase hyphenated output. Check redirect rules to confirm old underscore URLs are permanently (301) redirected to their hyphenated equivalents.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/seo/hyphens
