Your Performance Max campaign reports a ROAS of 5. You spent £10,000 and Google credits it with £50,000 of sales. How many of those sales needed the campaign?

Performance Max decides for itself where your ads show. Standard Shopping shows products in Shopping results only, and you control the rest.

Where the 5 comes from

Say break-even ROAS is 2.5 (the return a campaign needs to cover each sale’s costs; work it out in Easier Ads Budgeting or read how). The 5 looks safe. Now remove the credit for brand searches:

Sales credited£50,000
−
From people searching your brand£20,000
=
Sales from new demand£30,000

Those people already knew you. A cheap brand ad or an organic result would have found them. £30,000 on £10,000 is a ROAS of 3. Still above 2.5, but a thinner margin than the 5 suggested.

The rule

Judge Performance Max on what it finds that you would not have won anyway.

Step 1: fence off your brand

Run a separate campaign for your brand name and brand products, with higher priority than Performance Max. Brand clicks stay cheap and stay out of its numbers.

Step 2: judge Performance Max on its own

With brand out, the ROAS you see is nearer the truth. Set a target ROAS from your margin, not Google’s default. Wait 4 to 6 weeks before judging, because learning can use a few weeks of budget.

Feed it photos in every shape, some video and customer lists as audience signals. Gaps get filled with Google’s auto-made creative.

Step 3: use Standard Shopping where control pays

It gives you 3 things Performance Max does not:

  • Negative keywords by product group. Performance Max now takes campaign-level negatives. Standard Shopping lets you block searches for each ad group.
  • Product splits. Best sellers that keep 60p of each £1 and clearance lines that keep 15p need different targets. Performance Max blends them.
  • Search term detail. Performance Max groups some searches into themes.

Use it for the products where margins differ most, not every product.

When Performance Max works

Good assets, customer data to point it at, and enough conversions for results to settle. There is no fixed number: some accounts settle early, some never do. If results still swing week to week after 6 weeks, Standard Shopping with a target ROAS is usually steadier.

The checklist walks through the checks in order.

Not sure how much of your Performance Max result is real? Book a free call and we’ll read it with you.

Quick answers

What is Performance Max for ecommerce?

Performance Max (PMax) is a Google campaign type that serves your ads across Search, Shopping, Display, YouTube, Discover, Gmail and Maps from one campaign. You give it a product feed, images, video and text. Google decides where, when and to whom to show them.

Should I use Performance Max or Standard Shopping?

For most shops, both. Performance Max is the main campaign for finding new customers. A separate brand campaign, and Standard Shopping for products you want tight control of, sit alongside it.

What are the downsides of Performance Max?

You see less. Some placements and search terms are grouped or hidden, negatives apply only at campaign level, and it often claims credit for brand searches that would have converted anyway.

How many conversions does Performance Max need?

There is no fixed number. Some accounts settle early, some never do. If results still swing from week to week after 6 weeks, a Standard Shopping campaign with a target ROAS is usually steadier.

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