A URL slug is the part of a web address that comes after your domain name and identifies a specific page on your site. In the URL seobyzack.com/what-is-a-url-slug, the slug is what-is-a-url-slug, the human-readable identifier that tells both people and search engines what the page is about.
Most small-business owners never think about slugs. They publish a post, WordPress generates something automatic, and they move on. That is a persistent small leak that costs you clicks in search results, makes your links harder to share, and creates technical debt when you eventually want to clean things up. Slugs are one of the few SEO elements you fully control with zero cost and roughly thirty seconds of attention per page.
Slug vs. URL Structure: They Are Not the Same Thing
URL structure is the overall pattern your site uses: whether you include categories, dates, subfolders. The slug is just the final segment, the page-specific label at the end. Consider three URLs for the same article:
- seobyzack.com/blog/2024/05/what-is-a-url-slug
- seobyzack.com/seo-basics/what-is-a-url-slug
- seobyzack.com/what-is-a-url-slug
The structure differs in each case. But the slug is identical: what-is-a-url-slug.
Why Slugs Matter
Keywords in URLs are a very small ranking factor. If you’re hoping a perfect slug pulls you from page three to page one, it will not. But ranking is not the only reason to care.
The SERP signal
Your slug shows up in Google search results, directly under the title. A clean URL like /what-is-a-url-slug reads as relevant and trustworthy. A URL like /?p=4827 reads as garbage.
The share signal
People paste URLs into Slack, email, LinkedIn, and text messages constantly. A descriptive slug previews what the link is about before anyone clicks. Messy slugs invite suspicion.
The internal link signal
When someone links to your page using the URL as anchor text, a descriptive slug becomes descriptive anchor text. Modest but real SEO benefit.
Best Practices for Writing Slugs
- Use lowercase only. Most servers treat /About and /about as different URLs, creating duplicate-content risk.
- Separate words with hyphens, not underscores. Google treats hyphens as word separators.
- Keep it short, three to five words is the sweet spot. Long slugs get truncated.
- Make it descriptive. Someone should be able to guess the page topic from the slug alone.
- Include your target keyword, but only once. Keyword stuffing in URLs is obvious and counterproductive.
- Drop stop words when you can. “a,” “the,” “of,” “and,” “for” usually add length without meaning.
- Avoid special characters. Stick to letters, numbers, and hyphens.
Common Mistakes
| Mistake | Why It Hurts |
|---|---|
| Auto-generated IDs like /?p=123 | Zero descriptive value, looks broken in SERPs |
| Dates in the slug (/2022/03/article-name) | Ages content visibly |
| Overly long slugs | Truncated in search results |
| Special characters and uppercase | Cause URL-encoding issues |
| Changing slugs without redirects | Breaks every existing inbound link |
The date issue deserves a closer look. Including the year and month in every URL means evergreen content looks dated forever. If you wrote a definitive guide in 2019 and the URL says /2019/04/, users will assume the information is stale before they even click.
How WordPress Handles Slugs
WordPress gives you two levels of control: a site-wide URL structure and per-post slug overrides.
The site-wide setting lives at Settings > Permalinks. For most blogs and small-business sites, “Post name” is the right choice, it gives you a clean structure like yoursite.com/post-slug. Avoid the “Plain” option and avoid date-based structures unless you publish news.
The per-post override is in the block editor sidebar, under the URL or Permalink section. By default, WordPress generates a slug from your post title. Override it before publishing if the auto-generated version is too long.
When to Change a Slug
Almost never. Every existing link to your page, from other websites, your own past posts, social profiles, email signatures, bookmarks, points at the old slug. Changing breaks all of them unless you set up a 301 redirect.
Legitimate reasons to change: the current slug is genuinely broken (special characters, dates, auto-generated ID); the page topic has shifted; you’re consolidating two pages. Bad reasons: you thought of a slightly better keyword variation; you read an SEO post that recommended a different convention.
If you do change one, set up the 301 the same day. On WordPress, the Redirection plugin makes this trivial.
The Bottom Line
Slugs are a thirty-second decision per page. Get them right at publish time and you never have to think about them again. Get them wrong and you either live with the cost forever or pay the cleanup tax later.
If you’re launching a new post today: confirm your permalink structure is set to “Post name,” draft your title, then override the auto-generated slug to something short, lowercase, hyphenated, and descriptive. That is the whole job.