Does Google really merge similar pages into a single indexed version?

What does Google mean by "similar pages"?

Google compares the main textual content of each URL to detect substantial duplications. If two pages share 80% or more of identical text, the algorithm may consider them redundant, even if the URL, title, or a few blocks differ.

This handling primarily concerns multilingual or multi-regional sites where the structure remains the same but the language or currency changes. Google aims to avoid indexing ten nearly identical versions that would dilute the relevance of its results.

How does hreflang fit into this process?

The hreflang attribute tells Google about the relationships between language or geographical variants of the same page. When the engine detects a strong similarity, it selects a canonical version by default and uses hreflang to serve the correct alternative to the end user based on their language or location.

Without correctly configured hreflang, Google might randomly index an English version for a French user, or completely ignore some variants. The attribute acts as a navigation tag, not as a signal for content differentiation.

Why is this mechanism problematic for SEO?

If you publish truly distinct content across multiple URLs and Google deems them too close, it will consolidate indexing to a single page. Other variants risk disappearing from the SERPs, even if they target sightly different search intents.

E-commerce sites with product pages differentiated by color, size, or region often experience this phenomenon. Google prefers to index the generic version and ignore the variants unless the content is sufficiently enriched to justify separate indexing.

• Google favors the version it considers most relevant as canonical by default, even without an explicit tag.
• Hreflang does not force multiple indexing: it redirects the user; it does not guarantee that all variants will appear in the index.
• Textual similarity is the main criterion, not HTML structure or metadata.
• Pages with nearly identical content risk unwanted consolidation, even on a monolingual site.
• Differentiating 20 to 30% of the content may be enough to avoid merging, but no official threshold is provided.

Is this statement consistent with real-world observations?

Yes, but Google remains vague about the similarity threshold that triggers consolidation. In practice, it's seen that pages sharing more than 70-80% of identical content are often merged, especially if the unique text is limited to headers or footers.

Poorly configured multilingual sites regularly see their English version dominating indexing, even for French or German queries. Hreflang corrects user-facing display, but does not compensate for overly uniform content to force separate indexing. [To verify]: Google does not publish any official percentage of tolerable similarity before merging.

What nuances should be added?

Mueller discusses “very similar” without specifying if this includes pages with the same structure but different content blocks. An e-commerce template with different product descriptions should theoretically avoid merging, but real-world reports show otherwise when descriptions are short or generic.

Another point: the hreflang attribute is presented as a solution, while it merely redirects the user to the correct variant. If Google only indexes one version, hreflang becomes useless for non-indexed variants. It is a service tool, not a forced indexing lever.

In what cases does this rule not apply?

If your pages have substantial unique content (more than 300 different words per page) and each URL targets a distinct intent or audience, Google will normally index all variants. Issues arise with automatically generated content, lazy product sheets, or word-for-word translations.

Sites with a limited crawl budget or low domain authority suffer more from this consolidation: Google prefers to conserve its resources and indexes fewer variants. A site with high authority can get away with more redundancy before merging. [To verify]: no Google document quantifies the impact of domain authority on this tolerance threshold.

What concrete steps should be taken to avoid merging?

Enrich each page with at least 250 to 300 words of unique content: detailed descriptions, local testimonials, usage tips specific to the region or language. Google must perceive real added value for each URL.

On e-commerce sites, add customer reviews segmented by region, localized buying guides, or specific delivery information. Do not just translate the same text word-for-word: rephrase, adapt examples, change perspectives.

What mistakes should be completely avoided?

Do not rely on hreflang to force the indexing of nearly identical pages. The attribute indicates relationships; it does not guarantee that Google will index all variants. If the content is too close, hreflang will be correctly interpreted, but some pages will remain out of the index.

Avoid creating dozens of regional variants with identical content just to cover all markets. Google will consolidate, and you will lose crawl budget without gaining visibility. Focus on strategic markets with truly differentiated content.

How can I check if my site is compliant?

Use Search Console to identify indexed pages and those excluded due to duplication. Compare the number of URLs submitted via sitemap with the number actually indexed: a significant gap may signal unwanted consolidation.

Test your hreflang tags with the hreflang validation tool or the “International Targeting” report in Search Console. Ensure that each variant correctly points to its alternatives and that there are no syntax errors or missing reciprocity.

• Audit the unique content per page: aim for a minimum of 30% different text between variants.
• Check the hreflang configuration in the source code, XML sitemap, or HTTP headers.
• Monitor indexing via Search Console and compare it with the expected number of URLs.
• Test the display of variants from different geographic locations.
• Enrich consolidated pages with local elements: reviews, FAQs, regional guides.
• If you manage a large multilingual site with hundreds of variants, consider the support of a specialized SEO agency to audit the structure, optimize content, and ensure maximum indexing without dilution.