Duplicate Content Checker
Find out how much two pages have in common. The checker fetches both pages, removes navigation, headers, footers and sidebars (optional), and compares the remaining text in overlapping runs of five words. It reports a similarity score, the share of each page that also appears in the other and the longest shared passages, and compares titles, meta descriptions, H1s and canonical tags. You can also compare two pasted texts.
- Encrypted connection
- No sign-up
- Free to use
How to use Duplicate Content Checker
- Enter the first and second page URL.
- Keep “Ignore navigation…” on for content only.
- Click “Compare pages”.
- Read the verdict and the shared passages.
Duplicate Content Checker features
Similarity score
Shared five-word runs.
Coverage
How much of each page is shared.
Shared passages
The longest matching text.
Page details
Title, description, H1, canonical.
Text mode
Compare two pasted texts.
Safe fetching
Only public http(s) addresses are fetched.
When to use Duplicate Content Checker
- Checking product variants or location pages.
- Finding copied content from another site.
- Comparing http/https or mobile URLs.
- Reviewing rewritten content against the original.
Duplicate Content Checker FAQ
Is duplicate content penalised?
Not as such. Search engines pick one version to show and filter the rest, so duplicates compete with each other. Deliberate copying to manipulate rankings is a different matter.
What similarity is too high?
Above about 80% the pages are near duplicates. Between 50% and 80% they share large sections; consider merging them or making each one distinct.
How should I fix duplicates?
Use a canonical tag pointing to the preferred page, a 301 redirect if one page is not needed, or rewrite the pages so each serves its own purpose.
Does it check the whole web?
No. It compares the two pages you enter. Searching the web for copies needs a search index.
How the comparison works
Each text is split into words and every run of five consecutive words is compared. This “shingle” method finds shared passages even when they are surrounded by different text, and ignores word order beyond the five-word window.
Similarity is the share of all runs that appear in both texts. Coverage looks at each page separately: a short page copied entirely into a long one has 100% coverage but a lower overall similarity. The verdict uses the higher coverage.
Removing navigation and footers matters because templates repeat on every page; without it, two unrelated pages of the same site look more similar than they are.
Privacy: the address you enter is fetched by our server only to run this check. The downloaded HTML is passed to your browser for analysis and is not stored, and the results are not saved on our side. Requests are rate-limited to keep the service fair for everyone, so if you check many pages in a row you may need to wait a few minutes.
Limits: pages are read up to 2 MB of HTML, redirects are followed up to eight hops and each request has a short timeout. Pages behind a login, servers that block automated requests and content added only by JavaScript cannot be analysed this way; for those, copy the page source from your browser and use the paste option where it is available.
Tip: fix the problems marked red first, because they matter most. Yellow warnings are worth reviewing but are often harmless in context, and blue notes are information. After a change, run the check again to confirm the result – search engines pick up the change on their next visit to the page.