Amazon's Prime Day 2025 made history. As the first-ever four-day format of the annual shopping event, it delivered record sales, record items sold, and meaningful shifts in consumer behaviour that every brand selling on Amazon needs to understand.

At Vector Retail Media, we were on the ground managing campaigns for a diverse range of partners throughout the event. Here's what the data tells us - and what it means for your Amazon strategy for the rest of 2025.

The big picture: what Amazon reported

Amazon confirmed that Prime Day 2025 was its biggest ever across every metric. Several headline themes emerged from the platform's own reporting

An extended format, bigger impact. The shift from two to four days wasn't just an extension of time — it fundamentally changed the psychology of the event, giving consumers more opportunity to compare, research, and make considered purchases.

AI-powered discovery. Amazon's continued investment in Alexa+, Rufus, and AI Shopping Guides signals a clear strategic push towards intelligent, frictionless product discovery. The way customers find products is evolving fast, and Prime Day 2025 was the clearest evidence yet.

Independent sellers thriving. Small and medium-sized businesses achieved record sales during the event, underscoring Amazon's growing role as a growth engine for businesses of all sizes.

Everyday essentials holding their own. Alongside headline deals, household staples performed strongly - showing that consumers use Prime Day for both high-value planned purchases and practical, everyday savings.

UK Category Performance: the numbers that matter

Our data reveals which categories led the charge in the UK during Prime Day 2025.

Health & Personal Care was the standout performer, recording a 23% uplift versus year-to-date sales and generating £28.8m - a 13% increase on Prime Day 2024. Within the category, Vitamins & Minerals grew 23% year-on-year, Hydration Drinks were up 17%, and Herbal Supplements surged 34%.

Home & Kitchen Appliances delivered a 17.6% uplift versus YTD, generating £17.7m and growing 7.3% from Prime Day 2024.

Electronics & Photo produced a 15.7% uplift versus YTD, generating £31.1m - a 6% increase on the prior year's event.

Vector client performance

Our clients significantly outperformed the broader market. On average, Vector clients achieved a 73% uplift in Prime Day 2025 sales compared to their year-to-date baseline, with Prime Day 2025 sales up 47% versus Prime Day 2024.

One of the most striking findings was the performance pattern across the four days. Contrary to expectations of a mid-event slowdown, Day 4 was the strongest day for most of our clients. This points to a meaningful shift in consumer behaviour: less impulsive, more intentional shopping, with a significant final push as the event window closed.

What this means for advertisers

Sophisticated budget management is non-negotiable
CPCs were elevated throughout the event, making precise budget allocation and bid management essential. Our approach prioritised budget allocation over aggressive bidding, competing strategically on high-impact keywords rather than attempting to dominate every auction.

Traffic value extends beyond deal holders
The heightened platform traffic during Prime Day creates opportunities for brands regardless of whether they are running an official deal. With the right targeting strategy, brands not participating in Prime Day deals still achieved meaningful uplifts in revenue and visibility.

Look beyond immediate ROI
For growth-focused brands, Prime Day is about more than short-term return. Key metrics including New-to-Brand customers, sales velocity, and Subscribe & Save uptake provide a far more complete picture of long-term value generated during the event.

The strategic takeaway

The four-day Prime Day wasn't simply a longer event, it created a genuinely different consumer experience. With more time to compare and research, shoppers made more intentional purchases. For Amazon brands and their agencies, this demands sustained engagement across the full event window and agile, real-time budget management based on daily performance signals.

The brands that won in 2025 treated Prime Day as both a performance channel and a brand-building opportunity. That dual approach will be equally critical when the next major retail moment arrives.

Want to understand how your brand performed during Prime Day 2025, or how to apply these insights to your Q4 Amazon strategy?

Get in touch with the Vector Retail Media team.

"Our clients significantly outperformed the broader market. On average, Vector clients achieved a 73% uplift in Prime Day 2025 sales compared to their year-to-date baseline, with Prime Day 2025 sales up 47% versus Prime Day 2024."