PMax vs Search Budget Allocator
Stop guessing how to split your Google Ads budget. Get a data-driven recommendation based on your goal, vertical, and conversion volume — with the reasoning explained.
PMax vs Search: what's actually different
Search campaigns show ads to users actively searching for your keywords. You control which queries trigger your ads, how much you bid per query, and which landing pages to send traffic to. The signal is explicit intent: the user typed something.
Performance Max is a single campaign type that serves ads across every Google surface — Search, Shopping, Display, YouTube, Discover, Gmail — using machine learning to allocate spend automatically. You provide assets (headlines, images, videos) and a goal; Google decides where, when, and to whom to show them.
The fundamental trade-off: Search gives you control and transparency. PMax gives you reach and automation. Neither is universally better — the right split depends on how much data your account has, your business model, and how much cannibalisation risk you can tolerate.
How to read the allocation
The tool uses three signals to calibrate the recommendation:
PMax smart bidding needs a minimum signal to learn. Below 20 conversions/month, the algorithm is essentially guessing — your money trains the model with poor data. Above 50/month, PMax can start to outperform manual bidding in Search for volume-oriented goals. The tool weights Search heavily below that threshold.
Below €1,000/month, splitting between two campaign types risks both being underfunded. PMax needs scale to learn, and a Search campaign with €400/month may not accumulate enough data to optimise bids effectively either. Start focused, expand once volume grows.
PMax performs best where visual formats accelerate decisions — eCommerce and travel. It underperforms in B2B and local services, where buying cycles are long and intent-based Search is the primary driver. The tool applies a vertical adjustment on top of the baseline split.
PMax cannibalisation: the risk most accounts ignore
PMax has a well-documented tendency to bid on branded terms — queries where users search your company name and were going to convert anyway. When this happens, PMax "steals" easy conversions from organic or branded Search campaigns and inflates its reported ROAS.
The cannibalisation risk is proportional to your brand search volume. The higher it is, the more important it is to add brand exclusions to your PMax campaigns before scaling spend. Without exclusions, you may be paying for clicks you'd have gotten for free.
In Google Ads: Campaign → Settings → Brand exclusions. Add your brand name and common misspellings. Also create a separate branded Search campaign with exact match to own that traffic at lower CPCs.