Duplicate Content: Hosts, Parameters and Canonicals
By CodexierPublished 4 min read
When people hear duplicate content they think of copied text. On most small business sites the real problem is technical: the same page can be reached at several addresses, and Google has to guess which one to show. That splits signals between copies, wastes crawling and sometimes puts the wrong version in the results. This guide explains where the copies come from and how redirects and canonical tags consolidate them.
How duplicates happen
- The site answers on both www and non-www, and on both HTTP and HTTPS.
- Several domains, such as a .se and a .com, show the same site instead of redirecting.
- Trailing slashes, capital letters or index.html create variants of the same path.
- Tracking parameters from ads and newsletters, such as utm tags, create new URLs.
- Filters and sorting in webshops generate thousands of parameter combinations.
- The same product sits in several categories with a different path in each.
- Print versions, staging sites left open and paginated archives add more copies.
www, non-www and several domains
Host duplicates are the easiest to fix and the most important, since they affect every page. Decide on one preferred form, for example https with www, and make every other form redirect there permanently.
| Address typed | Should end up at |
|---|---|
| http://example.se | https://www.example.se |
| https://example.se | https://www.example.se |
| http://www.example.se | https://www.example.se |
| https://example.com and other owned domains | https://www.example.se, path preserved |
Redirects should keep the path, so an old link to a service page lands on the same service page, not the home page. Our guide on choosing a .se or .com domain covers the domain decision itself.
Parameters and filters
Parameters are the part after the question mark in a URL. They are useful for tracking and filtering, but every combination is a new address to a search engine. For a webshop with colour, size and sort filters, the number of combinations quickly exceeds the number of real pages many times over.
Tracking parameters
Canonical to the clean URL. Google usually handles these well, but the canonical makes it explicit.
Sorting
Canonical to the unsorted category. Sorting never deserves its own place in search results.
Filters with search demand
A filter such as a brand or a common category may deserve a real, static page with its own content and URL.
Filters without demand
Canonical to the category, and avoid linking to endless combinations in crawlable links.
Checking what Google chose
Google Search Console shows the truth. Use URL inspection on an important page to see the user-declared canonical and the Google-selected canonical. If they differ, something is sending mixed signals. The page indexing report lists pages marked as duplicates, and whether Google chose a different canonical than you. Our guide to Google Search Console for beginners shows where to find both.
When you do not need help: a small site on a modern platform often has canonicals set correctly already, and fixing the host redirects is a quick job for your hosting provider. When a webshop has filter URLs flooding the index, or Google keeps choosing the wrong pages, our SEO audit and technical fix covers it. See the pricing page or book a short call.
Frequently asked questions
Does Google penalise duplicate content?
Not for technical duplicates on your own site. Google picks one version and ignores the rest. The harm is that signals are split and Google may choose a version you did not want.
Should product descriptions copied from the manufacturer be rewritten?
Where you can, yes. Manufacturer text appears on many shops, so your page has little reason to rank above theirs. Start with your best-selling products and add your own details.
Is a canonical tag the same as a redirect?
No. A redirect sends visitors and search engines to another URL. A canonical keeps the page accessible for visitors but tells search engines which version to index. Use redirects for addresses nobody needs.
What about the same content in Swedish and English?
Translations are not duplicates. Use hreflang tags to link the language versions and give each version a canonical pointing to itself.
Find the duplicates on your site
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