# How to fix duplicate content, case by case

There is no duplicate content penalty. There is something worse in practice: Google picks one URL out of a group and ignores the others, and it does not always pick the one you wanted. This page lists the eight places duplicates come from on a real site, and the fix for each.

Updated 2026-09-15 · Source: https://porteur.ai/guides/how-to-fix-duplicate-content

## What Google actually does with duplicates

When Google finds several URLs with the same or nearly the same content, it groups them and chooses one as the canonical. That one can be indexed and ranked. The others are marked in Search Console as an alternate page with a proper canonical tag, or as a duplicate where Google chose a different canonical than you did.

The first of those two is normal and needs nothing. The second is the one to read, because it means Google disagreed with your declaration. The cost of duplicates is not a penalty. It is signals split across addresses, crawl spent on copies, and sometimes the wrong version of a page in the results.

> Deliberate duplication to manipulate rankings is a different matter and is covered by the spam policies. Accidental duplicates, the kind every site has, are a housekeeping problem.

## The eight sources of duplicates on a small site

| Source | What it looks like | The fix |
| --- | --- | --- |
| Protocol and host | http and https, www and non-www, all answering 200 | Pick one, 301 the others on every path, canonical to the chosen host |
| Trailing slash | /pricing and /pricing/ both answer | Pick one form, redirect the other, keep internal links consistent |
| Tracking parameters | /guides/getting-started?utm_source=newsletter | Self-referencing canonical to the clean URL, never link internally with UTMs |
| Sorting and filtering | /tools?sort=new, /tools?sort=old | Canonical to the unfiltered page, or index the few filters with real demand |
| Pagination | /guides?page=2 holding the same intro as page 1 | Each page self-canonical, unique title, no canonical to page one |
| Near-identical pages you wrote | Two guides answering the same question | Merge into the stronger URL and 301 the other |
| Syndication and republishing | Your post on your site and on a partner's | Ask for a canonical to your URL, or accept that theirs may rank |
| Boilerplate | Twenty pages whose only difference is a name | Rewrite so each holds something of its own, or cut them |

## How to find your duplicates in twenty minutes

1. **Try the four addresses of your home page** Request http and https, with and without www. Three of the four should redirect to the fourth in one hop. If two of them answer 200, that is your first fix.
2. **Read the Page indexing report** In Search Console, open the Not indexed reasons. Alternate page with proper canonical tag is expected. Duplicate without user-selected canonical and Duplicate, Google chose different canonical than user are the two lists to work through.
3. **Inspect one URL from each list** URL Inspection shows the canonical you declared and the one Google selected. When they differ, Google is telling you which page it considers the original.
4. **Search your own site for repeated titles** A crawl, or a site: search on a phrase from a title, shows pages that say the same thing. Two pages with the same title usually answer the same query.
5. **Check your sitemap** It should list only the canonical version of each page. A sitemap holding both slash and non-slash variants is telling Google you meant both.

## Which fix to use, and when

Four tools, and each has one job. Using the wrong one is how a duplicate becomes an invisible page.

- Redirect with a 301 when the duplicate has no reason to exist. It moves visitors and signals to the page you kept.
- Canonical when the duplicate must stay reachable for people: a filtered list, a URL with tracking parameters, a print view.
- Noindex when the page is useful to visitors and worthless in results, such as an internal search results page. Never combine it with a robots.txt block, because a blocked page cannot deliver its noindex.
- Rewrite when the pages are near-identical because you wrote them that way. A page that only differs by a swapped noun is the case Google's scaled content guidance describes.
- Leave it alone when Search Console says alternate page with proper canonical tag and the canonical points where you want. That is the system working.

> A canonical is a hint, not an order. Google can pick another URL, usually because the two pages are not as similar as you think, or because your internal links and sitemap point somewhere else.

## A worked example on yourproduct.com

Search Console lists 140 pages as Not indexed. The reasons break down into three groups, and each group has one fix.

- Sixty URLs with ?utm_source= from a newsletter, indexed as separate pages. They already carry a canonical to the clean URL, so Google folded them. Nothing to do except stop putting tracking parameters on internal links.
- Forty URLs under /blog/ with a trailing slash while the site links to the version without. Both answered 200. One redirect rule at the edge and an update to the sitemap fixed the group in a week.
- Two guides, /guides/getting-started and /guides/quick-start, both written for the same question, trading places on it. The longer one was kept, the better parts of the other folded in, and the second 301ed to the first.

A fixed site looks like this: one address per page, a self-referencing canonical on each, a sitemap that lists only those addresses, and internal links that all point at the same form.

## Duplicates across sites, which you control less

Your text can appear elsewhere without any mistake on your side. The options are narrower, and panic is usually the wrong response.

- Syndication: when a partner republishes your piece, ask for a canonical to your URL or a noindex on theirs. Without one, their version can be the one Google keeps.
- Manufacturer descriptions: a store using the supplier's text shares it with every other store. The fix is to write your own, which is also the only way those pages earn anything.
- Scrapers: sites that copy you automatically. Google is generally good at picking the original, and there is a removal request for the rare case it is not. It is not worth your week.
- Your own second domain: a marketing site and an app site with the same landing pages compete with each other. Pick one home for a page.

## What not to do

- Do not block duplicates in robots.txt. Google cannot then read the canonical or the noindex, and can still index the URL from links.
- Do not canonical every paginated page to page one. The items on page two then have no indexable home.
- Do not rewrite a page just to beat a similarity score in a tool. Google groups pages by what they are about, not by a percentage.
- Do not redirect a duplicate to the home page. That is read as a soft 404 and loses whatever the page had.
- Do not disavow links to a scraped copy of your page. The disavow file is for a manual action or a known paid history.

## Questions

### Is there a duplicate content penalty?

No. Google groups duplicates, picks one URL as the canonical and indexes that one. The cost is split signals, wasted crawl and sometimes the wrong version ranking, not a penalty. Deliberate duplication to manipulate rankings is covered separately by the spam policies.

### Should I use a canonical tag or a 301 redirect?

Redirect when the duplicate has no reason to exist for a visitor. Use a canonical when the URL must stay reachable, such as a filtered view or a link carrying tracking parameters. A redirect is stronger because it removes the choice.

### Why does Google show my page as a duplicate when I set a canonical?

A canonical is a hint. Google overrides it when the pages differ more than you think, when your internal links and sitemap point at another URL, or when the chosen page redirects. URL Inspection shows the canonical you declared next to the one Google selected.

### How much duplicate content is acceptable?

There is no percentage. Shared navigation, footers and boilerplate are normal on every site. The question is whether the main content of a page exists elsewhere on your site at another address, and whether each page holds something of its own.

### Do UTM parameters create duplicate content?

They create extra URLs. With a self-referencing canonical on the clean URL, Google folds them and nothing is lost. The rule that keeps it tidy is to use tracking parameters on links you place elsewhere, never on links inside your own site.

### What if another site copies my content?

Google usually identifies the original, especially when your page was crawled first and your site is the one linked. Keep your sitemap current so new pages are found quickly. For the rare persistent case there is a legal removal request; it is not an SEO problem to solve with redirects or disavows.

## Read next

- [Duplicate content](https://porteur.ai/glossary/duplicate-content): Learn what duplicate content is, how Google handles it, how to find it on a small site, and the exact controls to fix and prevent it.
- [Canonical tags: what they do and the mistakes that cost rankings](https://porteur.ai/guides/canonical-tag): What a canonical tag does, when to use one, the mistakes that cost rankings, and how to check and fix canonicals on a small site.
- [Duplicate without user-selected canonical: the fix in three steps](https://porteur.ai/guides/duplicate-without-user-selected-canonical): What the Search Console status means, where duplicates come from, how to pick the canonical, and the three steps to clear it for small product sites.
- [Alternate page with proper canonical tag: what Search Console means](https://porteur.ai/guides/alternate-page-with-proper-canonical-tag): What this Search Console status means, when to ignore it, when it hides the wrong page, and the exact checks and fixes to set the right canonical.
- [When to merge two pages, and how to do it without losing the ranking](https://porteur.ai/guides/when-to-merge-pages): Two pages target the same searches. Here is when to merge, which URL to keep, how to fold content, and how to redirect without losing the ranking.
- [Trailing slash: two URLs for one page unless you decide](https://porteur.ai/guides/trailing-slash-seo): Google sees /page and /page/ as different. Pick one form, redirect the other, and keep links and your sitemap consistent. Here is how to do it.
- [www or non-www: pick one, redirect the other](https://porteur.ai/guides/www-vs-non-www): Pick www or non-www, there is no SEO gain either way. 301 redirect every path to the chosen host, set canonicals, and verify a Domain property.
- [On-page SEO checker](https://porteur.ai/tools/on-page-seo-checker): Paste a URL and get the page read as a crawler reads it: title, description, canonical, indexability, headings, alt text, links, share tags, what to fix first.

Paste your URL and the free check reads your site the way a crawler does: the addresses that answer twice, the pages that say the same thing, and the three findings worth your next hour. Free check: https://porteur.ai/