December 2025 Core Update: Everything You Need to Know

Types of Websites Affected:

The December 2025 Core Update brought significant changes to search rankings, primarily impacting websites that:

• Run affiliate or review content without original first-hand testing or expert input.
• Publish "best of" listicles competing against established brand publishers.
• Score poorly on Core Web Vitals, especially LCP and INP at the 75th percentile.
• Rely on rewritten or aggregated content without unique analysis or perspective.
• Operate thin product comparison or SaaS comparison pages with no real research underneath.

What to Expect:

Websites affected by this update may experience:

• Major volatility on December 13 and December 20: Two distinct waves of ranking movement during the rollout.
• Brands gaining ground on "best of" queries: Established names took more visibility on commercial intent searches.
• A stronger Core Web Vitals tiebreaker: Sites with LCP over 3 seconds saw notably worse outcomes than faster competitors with similar content.
• Tighter E-E-A-T application across commercial verticals: SaaS, e-commerce, and how-to content saw E-E-A-T enforcement at levels previously reserved for YMYL topics.

What to Address / How to Approach:

To stay competitive after this update, website owners should:

1. Audit comparison and review pages: Add original testing, screenshots, pricing checks, and clearly named author expertise.
2. Fix Core Web Vitals: Target LCP under 2.5 seconds and INP under 200 milliseconds, measured at the 75th percentile of real user data.
3. Strengthen author and brand signals: Real authors, detailed bios, credentials, and clear publisher information matter more after this update.
4. Move beyond surface-level "best of" lists: Add genuine selection criteria, methodology, and use cases that demonstrate real research.
5. Watch for prolonged movement: Volatility extended well past the official December 29 end date for many sites, so do not act on a single week of data.

Interesting Fact 💡:

The December 2025 Core Update was the longest core update rollout of the year at 18 days, 2 hours. Analysis of affected sites found that pages with LCP above 3 seconds experienced roughly 23% more traffic loss than faster competitors with similar content, and poor INP scores above 300ms caused around 31% drops particularly on mobile, making this one of the first core updates where technical performance acted as a clear tiebreaker.

SEO Community Observations: Brand Visibility Shifts and Ranking Fluctuations

Search Engine Journal reported that brands won more "best of" queries during the December 2025 rollout, marking a clear shift toward brand authority in commercial searches. Barry Schwartz at Search Engine Land documented volatility spikes on December 13 and December 20, with continued ranking movement after the rollout completed. Multiple data providers including Semrush and Similarweb characterized this update as the most disruptive core update of 2025.