Google Clarifies Search Favicon Formats: 7 File Types Publishers Can Use

What Google clarified

Google’s Search documentation update log says the earlier favicon page pointed to an external format reference that changed over time. The new wording places the supported formats inside Google’s own documentation, removing that ambiguity.

The same update log states that Search’s supported file formats have not changed. A publisher should therefore describe this as clearer documentation. Claims that Google “added” TIFF, PPM, or another listed format would go beyond the source.

The format is only one eligibility condition

Google’s favicon guide requires a square image at least 8 by 8 pixels and recommends a size larger than 48 by 48 pixels. It also says Googlebot-Image must be able to crawl the image and Googlebot must be able to crawl the homepage.

Search supports one favicon per hostname. A domain and subdomain can use different favicons, but a subdirectory cannot declare a separate Search favicon for itself. That distinction matters for publishers that place sections under paths such as /news/ rather than dedicated hosts.

Google recommends keeping the favicon URL stable. Even a technically valid replacement is harder to process consistently if a build system creates a new hashed URL on every deployment.

Run this seven-part favicon audit

1. Resolve the homepage. Confirm the canonical hostname that Search should associate with the icon.
2. Inspect the rendered head. Find the relevant link rel="icon" declaration and record its resolved URL.
3. Fetch the image directly. Check for a successful response, an image content type, and no login, challenge, or redirect loop.
4. Check both crawler paths. Review robots rules for the homepage and favicon path rather than assuming browser visibility proves crawl access.
5. Measure the source. Verify a 1:1 aspect ratio and use a source comfortably above Google’s recommended 48-pixel threshold.
6. Keep the URL stable. Replace the file at a controlled versioned location only when the brand mark meaningfully changes.
7. Record the observation date. Search appearance can lag a deployment, and Google does not guarantee that an eligible favicon will appear.

This sequence separates four states that are often collapsed: declared in HTML, retrievable over HTTP, eligible under the documented guidelines, and actually shown in a search result. One state does not prove the next.

Common failures that a format change will not fix

Converting an icon from ICO to PNG will not repair a blocked image path, a blocked homepage, a rectangular source, or a declaration that points to a missing asset. It also will not create a separate favicon for a subdirectory.

A generic browser globe does not prove that Google rejected the file format. The cause could be processing delay, a conflicting declaration, a crawl problem, a hostname mismatch, or Google’s discretionary presentation. Start with the observable checks before changing the artwork.

For broader image selection questions, see how Google chooses Search and Discover thumbnails. A favicon and an article thumbnail are separate assets with different markup and presentation rules.

What to do after a favicon change

Deploy the homepage declaration and image together, clear the relevant caches, and verify the public response from a logged-out request. Save the previous file and declaration so the change is reversible.

Then wait for normal recrawling and record what appears. Google’s guide says favicon display is not guaranteed even when every guideline is met, so do not promise a deadline or treat a missing icon as evidence of a ranking problem. Include favicon verification in a wider technical SEO launch check instead of diagnosing it in isolation.

Source, method, and limit

Primary sources: Google’s favicon eligibility guide and Search documentation update log, checked September 4, 2026.

Information gain: this article turns the clarified format list into a seven-part audit that records declaration, retrieval, crawlability, geometry, hostname scope, URL stability, and observed display separately.

Limit: the audit diagnoses documented eligibility and delivery. It cannot force Google to show a favicon or establish why a particular result omitted one.