URL conventions often become a debate about whether hyphens or underscores are better for SEO. Google refreshed its URL structure guidance on October 23, 2026, clarifying the word-separation recommendation. The practical takeaway is straightforward for new routes: choose readable words and use hyphens between them. The more consequential decision is whether an existing URL should change at all.
What Google’s current URL guidance says
Google recommends separating words in URLs with hyphens rather than underscores. Its documentation explains that hyphens clearly signal word boundaries, while underscores have historically been used to join concepts in some programming contexts. The same guidance recommends descriptive URLs that are understandable to people, use the audience’s language, and avoid unnecessary parameters.
This is a best practice for making URLs clearer; it is not a promise of better rankings. A readable slug cannot compensate for a page that is inaccessible, duplicated, irrelevant, or unhelpful.
A simple pattern for new URLs
Use a short phrase that describes the page’s subject and matches how your audience refers to it. Keep the path lowercase if your server treats letter case as distinct, and use a consistent trailing-slash convention. Avoid stuffing multiple near-synonyms into a slug or encoding temporary campaign details that will quickly become stale.
| Prefer | Avoid when possible | Why |
|---|---|---|
/technical-seo-audit | /technical_seo_audit | Hyphens visibly separate the words |
/services/web-development | /page?id=48291 | Descriptive paths are easier to recognize |
/guides/search-console | /guides/Search-Console on a case-sensitive host | Consistent casing reduces duplicate URL variants |
Should you change old URLs?
Usually, not solely to replace underscores. Existing URLs may already have links, bookmarks, search history, analytics records, and canonical references. A rename creates another URL that search systems need to discover and reconcile. If the old route works and the page is useful, keep it unless a broader information-architecture change justifies the migration.
Consider changing a URL when it is misleading, exposes an unstable identifier, conflicts with a lasting site structure, or needs correction as part of a larger migration. Make that decision based on user clarity and maintainability, not a claim that a new punctuation choice guarantees a ranking gain.
Plan a URL migration before release
- List every old path and its intended new destination.
- Use a permanent server-side redirect from each old URL to its closest equivalent; avoid sending every old page to the homepage.
- Update internal links, canonical tags, structured data URLs, and sitemap entries to the new canonical paths.
- Check for redirect chains, loops, broken links, and pages that accidentally return success with missing content.
- After release, fetch representative URLs and review Search Console indexing and traffic over time.
Keep a record of the change date, affected routes, expected response, and rollback path. A redirect response proves that routing works; it does not by itself prove that Google has processed the move or that performance will remain identical.
Keep URL structure simple as the site grows
Readable URLs work best when they reflect a stable site structure. Use a small number of meaningful sections, keep related pages close together, and avoid creating endless filter or tracking-parameter combinations that lead to substantially identical content. Use query parameters when they genuinely change the view or state, and remove irrelevant ones where practical.
For a new project, agree on a slug convention before publishing many routes. For a mature site, document existing patterns and change them gradually with redirects and verification. Consistency and a correct destination matter more than a cosmetic rewrite.
Primary sources: Google Search Central documentation updates, October 23, 2026 · Google URL structure best practices · Google site moves with URL changes.