If you’re running an ecommerce business in the UK, you’ve likely heard about Google’s Performance Max (PMAX) campaigns. But what exactly makes them different from traditional search or shopping campaigns — and how can they help you scale profitably in 2025?
In this guide, we break down how to use PMAX campaigns in the UK ecommerce space, including best practices, smart bidding strategies, and the key mistakes to avoid.
What Is a PMAX Campaign?
Performance Max (PMAX) is Google’s all-in-one campaign type that allows advertisers to access all of Google’s inventory from a single campaign:
- Search
- Shopping
- YouTube
- Display
- Gmail
- Discover
Instead of managing multiple campaigns separately, PMAX uses AI and machine learning to automatically show your ads across the right channels, to the right people, at the right time.
Why UK Ecommerce Brands Should Use PMAX
PMAX is particularly powerful for ecommerce because it:
- Uses your product feed from Merchant Center
- Automatically optimises creative and placements
- Adjusts bids in real-time using smart bidding
- Unlocks new audiences beyond keyword-based search
If you’re already using Smart Shopping or Standard Shopping, PMAX is the next evolution — and in 2025, it’s where Google is putting most of its automation power.
PMAX Campaigns UK: Key Benefits
1. Unified Campaign = Less Management Time
You no longer need to manage separate campaigns for Search, Display, and YouTube. PMAX consolidates efforts and uses AI to allocate budget where it performs best.
2. AI-Powered Smart Bidding
With bidding strategies like Maximise Conversion Value or Target ROAS, Google automatically adjusts your bids based on:
- User intent
- Device type
- Time of day
- Historical performance
This is especially effective for large product catalogues where manual bidding becomes impossible.
Learn more about smart bidding in How to Generate More Local Leads with AI-Powered Google Ads.
3. Visual and Creative Flexibility
PMAX campaigns use asset groups — combinations of:
- Headlines
- Descriptions
- Images
- Video (optional but highly recommended)
Google mixes and matches these across placements to find the best-performing combinations.
For high-converting creatives, tools like AdCreative.ai and ChatGPT can help you generate compelling assets quickly. See 7 AI Tools Every Digital Marketer Should Use for Paid Ads for more.
Best Practices for Running PMAX Campaigns in the UK
1. Feed Quality Is Everything
Your Merchant Center product feed must be clean, complete, and optimised:
- Use high-quality images
- Optimise titles with relevant keywords
- Add product highlights and attributes
- Use custom labels for segmentation
If your product data is poor, PMAX won’t be able to perform at its best.
2. Set Clear Conversion Goals
Before launching PMAX, make sure you’ve defined your conversion actions clearly in Google Ads:
- Purchase events
- Add-to-cart or checkout steps
- Phone calls or form submissions (if relevant)
Without proper tracking, Google’s automation won’t know what to optimise for. Read more in 10 Costly Google Ads Mistakes UK Businesses Still Make in 2025.
3. Use Audience Signals — But Don’t Limit Learning
In PMAX, you can provide audience signals to help guide Google’s targeting — such as past purchasers, email lists, or in-market segments. But don’t treat these as strict targeting; think of them as suggestions.
Let Google’s AI find new audiences while keeping performance aligned with your goals.
4. Create Multiple Asset Groups for Key Product Categories
Rather than lumping your whole catalogue into one campaign, create separate asset groups for:
- Product categories
- Seasonal collections
- High-margin items
This allows better testing and more relevant ad messaging per group.
5. Monitor Insights and Adjust
PMAX campaigns provide a unique “Insights” tab where you can see:
- Top-performing search themes
- Audience segments
- Asset performance breakdown
Use this data to learn what’s working and refine your creative and messaging accordingly.
Common PMAX Mistakes to Avoid
- ❌ Using generic or low-quality images
- ❌ Neglecting your product feed quality
- ❌ Running PMAX without conversion tracking
- ❌ Skipping asset groups for category segmentation
- ❌ Over-controlling with too many exclusions or overlapping campaigns
Avoid these pitfalls to let Google’s AI work as intended.
Final Thoughts
Google PMAX campaigns offer ecommerce brands in the UK a powerful, AI-driven way to scale, especially when paired with clean data, strong creative, and a conversion-focused funnel.
In 2025, the brands that win with PMAX are those who embrace automation but guide it with strategy.